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All questions of April Week 3 for NEET Exam
A truck has a velocity of 2 m /s at time t=0. It accelerates at 2 m / s2 on seeing police .What is its velocity in m/s at a time of 2 sec- a)6
- b)7
- c)3
- d)4
Correct answer is option 'A'. Can you explain this answer?
A truck has a velocity of 2 m /s at time t=0. It accelerates at 2 m / s2 on seeing police .What is its velocity in m/s at a time of 2 sec
a)
6
b)
7
c)
3
d)
4
 | Naina Sharma answered |
Explanation:
Initial velocity u = 2 m/s
final velocity = v m/s
Time duration = final time - initial time = 2-0 = 2 s
acceleration a = 2 m/s2
We know,
v = u + at
=> v = 2+2x2
=> v = 6 m/s
If the position- time graph is a straight line parallel to the time axis- a)The velocity is zero
- b)The velocity is decreasing
- c)The velocity is increasing
- d)The velocity is constant but non zero
Correct answer is option 'A'. Can you explain this answer?
If the position- time graph is a straight line parallel to the time axis
a)
The velocity is zero
b)
The velocity is decreasing
c)
The velocity is increasing
d)
The velocity is constant but non zero
| | Neha Sharma answered |
Explanation:Position-time graph of horizontal straight line parallel to time axis represents that the position of the body does not changes with the passage of time. So it represents the rest state of motion.It means velocity of object is zero.
An object is said to be in uniform motion in a straight line if its displacement- a)is decreasing in equal intervals of time
- b)is increasing in equal intervals of time
- c)is equal in equal intervals of time.
- d)is equal in not equal intervals of time.
Correct answer is option 'C'. Can you explain this answer?
An object is said to be in uniform motion in a straight line if its displacement
a)
is decreasing in equal intervals of time
b)
is increasing in equal intervals of time
c)
is equal in equal intervals of time.
d)
is equal in not equal intervals of time.
 | Mira Joshi answered |
Explanation:Uniform motion is the kind of motion in which a body covers equal displacement in equal intervals of time. It does not matter how small the time intervals are, as long as the displacements covered are equal.
If a body is involved in rectilinear motion and the motion is uniform, then the acceleration of the body must be zero.
Which of the following organisms have been placed under kingdom Protista?- a)Chrysophytes and dinoflagellates
- b)Euglenoids
- c)Slime moulds and protozoans
- d)All of these
Correct answer is option 'D'. Can you explain this answer?
Which of the following organisms have been placed under kingdom Protista?
a)
Chrysophytes and dinoflagellates
b)
Euglenoids
c)
Slime moulds and protozoans
d)
All of these
| | Mira Joshi answered |
The kingdom protista has been broadly divided into three main groups:
(i) Photosynthetic Protists (Protistan Algae) e.g., Dinoflagellates, Chrysophytes and Euglenoids
(ii) Consumer-Decomposer Protists(Slime Moulds)
(iii) Protozoan Protists
Euglenoids are Euglena like unicellular glagellates which posess pellicle instead of cell wall. Chrysophytes include diatoms and desmids. They belong to the division Chrysophyta/Bacillariophyta. The dinoflagellates belong to division Pyrrophyta and class Dinophyceae. Slime moulds possess the characters of both animals and fungi and , therefore they are commonly called fungus-animals.
(i) Photosynthetic Protists (Protistan Algae) e.g., Dinoflagellates, Chrysophytes and Euglenoids
(ii) Consumer-Decomposer Protists(Slime Moulds)
(iii) Protozoan Protists
Euglenoids are Euglena like unicellular glagellates which posess pellicle instead of cell wall. Chrysophytes include diatoms and desmids. They belong to the division Chrysophyta/Bacillariophyta. The dinoflagellates belong to division Pyrrophyta and class Dinophyceae. Slime moulds possess the characters of both animals and fungi and , therefore they are commonly called fungus-animals.
The dimensional formula for acceleration is- a)[LT2]
- b)[LT-2]
- c)[L2T]
- d)[L2T2]
Correct answer is option 'B'. Can you explain this answer?
The dimensional formula for acceleration is
a)
[LT2]
b)
[LT-2]
c)
[L2T]
d)
[L2T2]
 | Upasana Bose answered |
Acceleration is the rate of change of velocity of an object with respect to time. It is a vector quantity and its direction is the same as that of the change in velocity. The dimensional formula for acceleration is given by LT-2, where L stands for length and T stands for time.
Explanation:
Acceleration can be mathematically represented as:
a = (v-u)/t
where a is the acceleration, v is the final velocity, u is the initial velocity and t is the time taken to change the velocity.
Dimensional formula for velocity is LT-1, as velocity is distance travelled per unit time. Therefore, the dimensional formula for acceleration can be obtained by dividing the dimensional formula for velocity by the dimensional formula for time.
a = (v-u)/t = (LT-1 - LT-1)/T = LT-2
Hence, the correct answer is option B, LT-2.
Conclusion:
In conclusion, the dimensional formula for acceleration is LT-2, which means that acceleration is directly proportional to length and inversely proportional to time squared. It is important to understand the dimensional formula of a physical quantity as it helps in formulating equations and understanding the physical nature of the quantity.
Explanation:
Acceleration can be mathematically represented as:
a = (v-u)/t
where a is the acceleration, v is the final velocity, u is the initial velocity and t is the time taken to change the velocity.
Dimensional formula for velocity is LT-1, as velocity is distance travelled per unit time. Therefore, the dimensional formula for acceleration can be obtained by dividing the dimensional formula for velocity by the dimensional formula for time.
a = (v-u)/t = (LT-1 - LT-1)/T = LT-2
Hence, the correct answer is option B, LT-2.
Conclusion:
In conclusion, the dimensional formula for acceleration is LT-2, which means that acceleration is directly proportional to length and inversely proportional to time squared. It is important to understand the dimensional formula of a physical quantity as it helps in formulating equations and understanding the physical nature of the quantity.
A compound contains two elements 'x' and 'Y' in the ratio of 50% each. Atomic mass of 'x' is 20 and 'Y' is 40. What can be its simplest formula?- a)XY
- b)X2Y
- c)XY2
- d)X2Y3
Correct answer is option 'B'. Can you explain this answer?
A compound contains two elements 'x' and 'Y' in the ratio of 50% each. Atomic mass of 'x' is 20 and 'Y' is 40. What can be its simplest formula?
a)
XY
b)
X2Y
c)
XY2
d)
X2Y3
 | Gayatri Singh answered |
Explanation:
To determine the simplest formula of a compound, we need to find the ratio of the elements present in the compound. In this case, the compound contains two elements, X and Y, in a ratio of 50% each.
Step 1: Determine the atomic masses of X and Y
The atomic mass of X is given as 20, and the atomic mass of Y is given as 40.
Step 2: Convert the atomic masses to moles
To find the ratio of the elements, we need to convert the atomic masses to moles by dividing them by their respective atomic masses.
Moles of X = 20/20 = 1
Moles of Y = 40/40 = 1
Step 3: Determine the simplest ratio of X and Y
Since the ratio of X and Y is 1:1, the simplest ratio can be expressed as X1Y1, which can be simplified to XY.
Step 4: Write the simplest formula
The simplest formula of the compound is XY.
Therefore, the correct answer is option B, XY.
Note: It is important to note that the ratio of elements in a compound is determined by the number of moles, not the percentage. The 50% each mentioned in the question is used to determine the ratio of the elements, but the ratio is expressed in moles, not percentages.
To determine the simplest formula of a compound, we need to find the ratio of the elements present in the compound. In this case, the compound contains two elements, X and Y, in a ratio of 50% each.
Step 1: Determine the atomic masses of X and Y
The atomic mass of X is given as 20, and the atomic mass of Y is given as 40.
Step 2: Convert the atomic masses to moles
To find the ratio of the elements, we need to convert the atomic masses to moles by dividing them by their respective atomic masses.
Moles of X = 20/20 = 1
Moles of Y = 40/40 = 1
Step 3: Determine the simplest ratio of X and Y
Since the ratio of X and Y is 1:1, the simplest ratio can be expressed as X1Y1, which can be simplified to XY.
Step 4: Write the simplest formula
The simplest formula of the compound is XY.
Therefore, the correct answer is option B, XY.
Note: It is important to note that the ratio of elements in a compound is determined by the number of moles, not the percentage. The 50% each mentioned in the question is used to determine the ratio of the elements, but the ratio is expressed in moles, not percentages.
The position of an object moving in a straight line can be specified with reference to- a)another straight line
- b)an arbitrary star
- c)a conveniently chosen origin
- d)a triangle
Correct answer is option 'C'. Can you explain this answer?
The position of an object moving in a straight line can be specified with reference to
a)
another straight line
b)
an arbitrary star
c)
a conveniently chosen origin
d)
a triangle
 | Pooja Shah answered |
Explanation:To describe motion along a straight line, we can choose an axis, say X-axis, so that it coincides with the path of the object. We then measure the position of the object with reference to a conveniently chosen origin, say O, Positions to the right of O are taken as positive and to the left of O, as negative.
Path length is a- a)vector
- b)derived unit
- c)scalar
- d)tensor
Correct answer is option 'C'. Can you explain this answer?
Path length is a
a)
vector
b)
derived unit
c)
scalar
d)
tensor
 | Om Desai answered |
Explanation:Path length has no particular direction and it depends upon the path chosen to reach the destination where displacement of the destination is absolute no matter what path is used to get there. So it is scaler.
A body moving with uniform acceleration has a velocity of 12.0 cm/s in the positive x direction when its x coordinate is 3.00 cm. If its x coordinate 2.00 s later is -5.00 cm, what is the magnitude of its acceleration in cm/s2 ?- a)-16.0 cm/s2
- b)-14.0 cm/s2
- c)-12.0 cm/s2
- d)-18.0 cm/s2
Correct answer is option 'A'. Can you explain this answer?
A body moving with uniform acceleration has a velocity of 12.0 cm/s in the positive x direction when its x coordinate is 3.00 cm. If its x coordinate 2.00 s later is -5.00 cm, what is the magnitude of its acceleration in cm/s2 ?
a)
-16.0 cm/s2
b)
-14.0 cm/s2
c)
-12.0 cm/s2
d)
-18.0 cm/s2
 | Rashmi Saxena answered |
DV=DX/dt=-5-3=-8/2=-4 Da=-dv/dt=-4-12=-16 we are not dividing with t because we have already found the displacement change at that time
The average acceleration a over a time interval is defined as- a)average velocity divided by the time interval
- b)the change of velocity divided by the time interval
- c)average speed divided by the time interval
- d)average displacement divided by the time interval
Correct answer is option 'B'. Can you explain this answer?
The average acceleration a over a time interval is defined as
a)
average velocity divided by the time interval
b)
the change of velocity divided by the time interval
c)
average speed divided by the time interval
d)
average displacement divided by the time interval
 | Sai Mishra answered |
Explanation:
Acceleration is the rate of change of velocity with time.It is a vector quantity.
Average acceleration is the change in velocity per unit time over an interval of time.
Let initial velocity at time interval t1 is v1 and final velocity at time interval t2 is v2 Then
Path length is defined as.- a)the total length of the path traversed by an object
- b)the distance from origin to maximum point
- c)distance from origin to origin.
- d)the distance from origin to minimum point
Correct answer is option 'A'. Can you explain this answer?
Path length is defined as.
a)
the total length of the path traversed by an object
b)
the distance from origin to maximum point
c)
distance from origin to origin.
d)
the distance from origin to minimum point
 | Arindam Unni answered |
Explanation:Path length is defined as the total length of the path traversed by an object.
Unlike displacement, which is the total distance an object travels from a starting point, path length is the total distance travelled, regardless of where it travelled.
Diatomaceous earth is used for all except- a)polishing
- b)filtration of oils and syrups
- c)making sound and fire proof rooms
- d)biogas production.
Correct answer is option 'D'. Can you explain this answer?
Diatomaceous earth is used for all except
a)
polishing
b)
filtration of oils and syrups
c)
making sound and fire proof rooms
d)
biogas production.
| | Mira Joshi answered |
Diatomite deposits are often accompanied by petroleum fields. Much of the petroleum of today is probably due to decayed bodies of the past diatoms. Diatomite is porous and chemically inert. It is, therefore, used in filtration of sugar, alcohols, oil, syrups and antibiotics. Diatomaceous earth is used to make sound proofrooms. Diatomite is employed as a cleaning agent in tooth pastes and metal polishes.
Choose the molecular formula of an oxide of iron in which the mass per cent of iron and oxygen are 69.9 and 30.1 respectively and its molecular mass is 160.- a)FeO
- b)Fe3O4
- c)Fe2O3
- d)FeO2
Correct answer is option 'C'. Can you explain this answer?
Choose the molecular formula of an oxide of iron in which the mass per cent of iron and oxygen are 69.9 and 30.1 respectively and its molecular mass is 160.
a)
FeO
b)
Fe3O4
c)
Fe2O3
d)
FeO2
| | Riya Banerjee answered |
For element Fe, mole of atoms = 69.9/56 = 1.25
For element O, Mole of atoms = 30.1/16 = 1.88
Mole ratio of Fe = 1.25/1.25 = 1
Mole ratio of O = 1.88/1.25 = 1.5
Simplest whole number ratio of Fe and O = 2, 3
Empirical formula of compoimd = Fe2O3
Molecular mass of Fe2O3 = 160
Molecular formula = Fe2O3
For element O, Mole of atoms = 30.1/16 = 1.88
Mole ratio of Fe = 1.25/1.25 = 1
Mole ratio of O = 1.88/1.25 = 1.5
Simplest whole number ratio of Fe and O = 2, 3
Empirical formula of compoimd = Fe2O3
Molecular mass of Fe2O3 = 160
Molecular formula = Fe2O3
How do slime moulds typically behave under favorable conditions?- a)They form fruiting bodies
- b)They differentiate to form fruiting bodies
- c)They disperse spores by air currents
- d)They engulf organic material
Correct answer is option 'D'. Can you explain this answer?
How do slime moulds typically behave under favorable conditions?
a)
They form fruiting bodies
b)
They differentiate to form fruiting bodies
c)
They disperse spores by air currents
d)
They engulf organic material
 | Ambition Institute answered |
Slime moulds, under favorable conditions, move along decaying twigs and leaves engulfing organic material. This behavior allows them to thrive by feeding on organic matter and growing as a result.
. During unfavourable conditions, the plasmodium differentiates and forms fruiting bodies bearing spores at their tips. The spores possess true walls. They are extremely resistant and survive for many years, even under adverse conditions. The spores are dispersed by air currents.
Protozoans obtain their food as- a)predators or parasites
- b)chemosynthesizers
- c) heterotrophs
- d)Both (A) and (C)
Correct answer is option 'D'. Can you explain this answer?
Protozoans obtain their food as
a)
predators or parasites
b)
chemosynthesizers
c)
heterotrophs
d)
Both (A) and (C)
 | Ciel Knowledge answered |
All protozoans are heterotrophs and live as predators or parasites.
Protista differs from monera in having- a)Cell wall
- b)Autotrophic nutrition
- c) flagella
- d)Nuclear membrane
Correct answer is option 'D'. Can you explain this answer?
Protista differs from monera in having
a)
Cell wall
b)
Autotrophic nutrition
c)
flagella
d)
Nuclear membrane
| | Ciel Knowledge answered |
- Correct Answer: D: Nuclear membrane
- Explanation:
- Protista is a kingdom of eukaryotic organisms, which means they have a true nucleus enclosed within a nuclear membrane.
- Monera, on the other hand, are prokaryotic organisms lacking a true nucleus and nuclear membrane.
- The presence of a nuclear membrane is a key characteristic that distinguishes Protista from Monera.
This distinction is crucial in understanding the fundamental differences between these two groups of organisms.
- Explanation:
- Protista is a kingdom of eukaryotic organisms, which means they have a true nucleus enclosed within a nuclear membrane.
- Monera, on the other hand, are prokaryotic organisms lacking a true nucleus and nuclear membrane.
- The presence of a nuclear membrane is a key characteristic that distinguishes Protista from Monera.
This distinction is crucial in understanding the fundamental differences between these two groups of organisms.
Name the instrument used to measure instantaneous speed of a vehicle.- a)multimeter
- b)accelerator
- c)speedometer
- d)ammeter
Correct answer is option 'C'. Can you explain this answer?
Name the instrument used to measure instantaneous speed of a vehicle.
a)
multimeter
b)
accelerator
c)
speedometer
d)
ammeter
 | Naveen Chavan answered |
Understanding the Speedometer
A speedometer is a crucial instrument in vehicles that provides real-time information about the speed at which the vehicle is traveling.
Functionality
- Instantaneous Speed Measurement: The primary role of a speedometer is to measure the instantaneous speed of the vehicle. This means it shows how fast the vehicle is moving at any given moment.
- Types of Speedometers: There are two main types: mechanical and electronic. Mechanical speedometers use a flexible, spinning cable connected to the vehicle's transmission, while electronic speedometers rely on sensors and digital displays.
Importance in Driving
- Safety: Monitoring speed is vital for safe driving. It helps drivers adhere to speed limits and avoid accidents due to speeding.
- Fuel Efficiency: Keeping an eye on speed can also improve fuel efficiency, as driving at optimal speeds reduces fuel consumption.
Comparison with Other Instruments
- Multimeter: This instrument measures electrical properties such as voltage, current, and resistance, and is not related to vehicle speed.
- Accelerator: While the accelerator pedal controls the vehicle's speed or acceleration, it does not measure speed.
- Ammeter: Like the multimeter, an ammeter measures electric current, making it irrelevant to vehicle speed.
Conclusion
In summary, the correct answer to the question is option 'C', the speedometer, as it is specifically designed to measure and display the instantaneous speed of a vehicle, which is essential for safe and efficient driving.
A speedometer is a crucial instrument in vehicles that provides real-time information about the speed at which the vehicle is traveling.
Functionality
- Instantaneous Speed Measurement: The primary role of a speedometer is to measure the instantaneous speed of the vehicle. This means it shows how fast the vehicle is moving at any given moment.
- Types of Speedometers: There are two main types: mechanical and electronic. Mechanical speedometers use a flexible, spinning cable connected to the vehicle's transmission, while electronic speedometers rely on sensors and digital displays.
Importance in Driving
- Safety: Monitoring speed is vital for safe driving. It helps drivers adhere to speed limits and avoid accidents due to speeding.
- Fuel Efficiency: Keeping an eye on speed can also improve fuel efficiency, as driving at optimal speeds reduces fuel consumption.
Comparison with Other Instruments
- Multimeter: This instrument measures electrical properties such as voltage, current, and resistance, and is not related to vehicle speed.
- Accelerator: While the accelerator pedal controls the vehicle's speed or acceleration, it does not measure speed.
- Ammeter: Like the multimeter, an ammeter measures electric current, making it irrelevant to vehicle speed.
Conclusion
In summary, the correct answer to the question is option 'C', the speedometer, as it is specifically designed to measure and display the instantaneous speed of a vehicle, which is essential for safe and efficient driving.
For motion with uniform acceleration, v-t graph is- a)a straight line parallel to the time axis
- b)a straight line perpendicular to the time axis
- c)a straight line inclined to the time axis.
- d)an ellipse
Correct answer is option 'C'. Can you explain this answer?
For motion with uniform acceleration, v-t graph is
a)
a straight line parallel to the time axis
b)
a straight line perpendicular to the time axis
c)
a straight line inclined to the time axis.
d)
an ellipse
 | Swara Bose answered |
Explanation:When velocity – time graph is plotted for an object moving with uniform acceleration, the slope of the graph is a straight line.
Displacement is a- a)Hector
- b)Vector
- c)Scalar
- d)Tensor
Correct answer is option 'B'. Can you explain this answer?
Displacement is a
a)
Hector
b)
Vector
c)
Scalar
d)
Tensor
 | Maheshwar Chawla answered |
Explanation:Displacement vector is a vector which gives the position of a point with reference to a point other than the origin of the coordinate system.
A compound contains 40% carbon, 6.67% hydrogen, and 53.33% oxygen. The empirical formula is:- a)CH₂O
- b)C₂H₄O₂
- c)CHO
- d)C₃H₆O₃
Correct answer is option 'A'. Can you explain this answer?
a)
CH₂O
b)
C₂H₄O₂
c)
CHO
d)
C₃H₆O₃
 | Top Rankers answered |
Correct Option - A
The correct answer is Option A - CH₂O
Take a 100 g sample so that the element masses become 40 g (carbon), 6.67 g (hydrogen) and 53.33 g (oxygen).
Convert masses to moles using atomic masses 12 for C, 1 for H and 16 for O: moles of C = 40/12 ≈ 3.33, moles of H = 6.67/1 = 6.67, moles of O = 53.33/16 ≈ 3.33.
Divide each mole value by the smallest mole number (3.33) to get the simplest whole-number ratio: C : H : O = 1 : 2 : 1.
Therefore the empirical formula is CH₂O.
Note: the molecular formula could be a whole-number multiple of the empirical formula, but with only percentage composition given the empirical formula CH₂O is the correct result.
A slide under microscope shows following features:
(i) Unicellularity
(ii) Well defined nucleus
(iii) Biflagellate-one flagellum lying longitudinally and the other transversely.
What would you identify it as?- a)Protozoan
- b)Bacterium
- c)Euglenoid
- d)Dinoflagellate
Correct answer is option 'D'. Can you explain this answer?
A slide under microscope shows following features:
(i) Unicellularity
(ii) Well defined nucleus
(iii) Biflagellate-one flagellum lying longitudinally and the other transversely.
What would you identify it as?
(i) Unicellularity
(ii) Well defined nucleus
(iii) Biflagellate-one flagellum lying longitudinally and the other transversely.
What would you identify it as?
a)
Protozoan
b)
Bacterium
c)
Euglenoid
d)
Dinoflagellate
| | Mira Joshi answered |
Dinoflagellates are basically unicellular, motile and biflagellate, golden brown, photosynthetic protists. The two flagella are different (heterokont), one transverse flagellum and other longitudinal flagellum.The longitudinal flagellum is narrow, smooth, directed posteriorly and lies in the sulcys. The transverse flagellum is ribbon-like and lies in the cingulum or annulus. The two types of flagella beat in different directions. A well defined nucleus is present, which has been named as mesokaryon.
Which of the following statements about Euglena is correct?- a)Euglena is a flagellate organism.
- b)Euglena when placed in continuous darkness, loses its photosynthetic activity and dies.
- c)The pigments of Euglena are quite different from those of green plants.
- d)Euglena is a marine protist.
Correct answer is option 'A'. Can you explain this answer?
Which of the following statements about Euglena is correct?
a)
Euglena is a flagellate organism.
b)
Euglena when placed in continuous darkness, loses its photosynthetic activity and dies.
c)
The pigments of Euglena are quite different from those of green plants.
d)
Euglena is a marine protist.
| | Mira Joshi answered |
Euglenoids are unicellular flagellate protists commonly found in fresh water ponds, pools and moist mud. They lack cellulose cell wall. The body is covered bv thin and flexible pellicle (= periplast). The pellicle has oblique but parallel stripes called myonemes. The euglenolds have two flagella, usually one long and one short. Though the euglenoids are photosynthetic in the presence of light, when deprived of sunlight they behave like heterotrophs by predating on smaller organisms (holozoic) or feeding on organic remains (saprobic). Such a mode of nutrition is called mixotrophic (i.e., a mix of holophytic + saprobic or holozoic). Photosynthetic pigments of euglenoids are identical to those present in higher plants, e.g. chl a and chl b.
The cell wall is composed of two thin overlapping shells which fit together like a soap case, in- a)desmids
- b)diatoms
- c)dinoflagellates
- d)slime moulds.
Correct answer is option 'B'. Can you explain this answer?
The cell wall is composed of two thin overlapping shells which fit together like a soap case, in
a)
desmids
b)
diatoms
c)
dinoflagellates
d)
slime moulds.
| | Mira Joshi answered |
The body of diatoms is covered by a transparent ' siliceous shell (silica deposited in cell wall) known as frustule. The frustule is made of two valves, epitheca and hypotheca. The two valves fit together like a soap box. The frustule possesses very fine markings, pits, pores and ridges.
Assertion (A): All protozoans are heterotrophs and primarily live as predators or parasites.Reason (R): Protozoans possess chloroplasts that allow them to perform photosynthesis.- a)If both Assertion and Reason are true and Reason is the correct explanation of Assertion
- b)If both Assertion and Reason are true but Reason is not the correct explanation of Assertion
- c)If Assertion is true but Reason is false
- d)If both Assertion and Reason are false
Correct answer is option 'C'. Can you explain this answer?
Assertion (A): All protozoans are heterotrophs and primarily live as predators or parasites.
Reason (R): Protozoans possess chloroplasts that allow them to perform photosynthesis.
a)
If both Assertion and Reason are true and Reason is the correct explanation of Assertion
b)
If both Assertion and Reason are true but Reason is not the correct explanation of Assertion
c)
If Assertion is true but Reason is false
d)
If both Assertion and Reason are false
 | Stepway Academy answered |
- The Assertion (A) is correct because it accurately describes the nutritional habits of protozoans as heterotrophs that mostly function as predators or parasites.
- The Reason (R) is false since protozoans do not possess chloroplasts and cannot perform photosynthesis; they are dependent on other organisms for nutrition.
- Therefore, the Reason is not the correct explanation of the Assertion. Since the Assertion is true and the Reason is false, the correct option is Option C.
The area under the velocity-time curve between times t1 and t2 is equal to the.- a)average velocity of the object during that interval of time
- b)path length of the object during that interval of time
- c)velocity of the object during that interval of time
- d)displacement of the object during that interval of time
Correct answer is option 'D'. Can you explain this answer?
The area under the velocity-time curve between times t1 and t2 is equal to the.
a)
average velocity of the object during that interval of time
b)
path length of the object during that interval of time
c)
velocity of the object during that interval of time
d)
displacement of the object during that interval of time
| | Swara Bose answered |
Explanation:
The area under the velocity-time curve represents the displacement of the object during that interval of time. This can be explained using the basic concept of calculus and the relationship between velocity and displacement.
Understanding the velocity-time curve:
The velocity-time curve represents how the velocity of an object changes over time. The velocity is plotted on the y-axis, and time is plotted on the x-axis. The shape of the curve depends on the motion of the object. For example, if the object is moving with constant velocity, the curve will be a straight line parallel to the x-axis. If the object is accelerating or decelerating, the curve will be curved.
Using calculus to find displacement:
To find the displacement of an object during a given interval of time, we can use calculus and integrate the velocity function with respect to time. Integration represents the area under the curve.
Explanation of the options:
a) Average velocity of the object during that interval of time: The average velocity is calculated by dividing the total displacement by the total time. It is not directly related to the area under the velocity-time curve.
b) Path length of the object during that interval of time: The path length is the total distance traveled by the object. It is not directly related to the area under the velocity-time curve.
c) Velocity of the object during that interval of time: The velocity of the object at a specific time can be determined from the velocity-time curve. However, the area under the curve does not represent the instantaneous velocity at any particular time.
d) Displacement of the object during that interval of time: The area under the velocity-time curve represents the change in displacement of the object during that interval of time. By integrating the velocity function, we can find the total area under the curve, which gives us the displacement.
Conclusion:
The area under the velocity-time curve between times t1 and t2 represents the displacement of the object during that interval of time. This is because integration of the velocity function gives us the total area under the curve, which represents the change in displacement.
The area under the velocity-time curve represents the displacement of the object during that interval of time. This can be explained using the basic concept of calculus and the relationship between velocity and displacement.
Understanding the velocity-time curve:
The velocity-time curve represents how the velocity of an object changes over time. The velocity is plotted on the y-axis, and time is plotted on the x-axis. The shape of the curve depends on the motion of the object. For example, if the object is moving with constant velocity, the curve will be a straight line parallel to the x-axis. If the object is accelerating or decelerating, the curve will be curved.
Using calculus to find displacement:
To find the displacement of an object during a given interval of time, we can use calculus and integrate the velocity function with respect to time. Integration represents the area under the curve.
Explanation of the options:
a) Average velocity of the object during that interval of time: The average velocity is calculated by dividing the total displacement by the total time. It is not directly related to the area under the velocity-time curve.
b) Path length of the object during that interval of time: The path length is the total distance traveled by the object. It is not directly related to the area under the velocity-time curve.
c) Velocity of the object during that interval of time: The velocity of the object at a specific time can be determined from the velocity-time curve. However, the area under the curve does not represent the instantaneous velocity at any particular time.
d) Displacement of the object during that interval of time: The area under the velocity-time curve represents the change in displacement of the object during that interval of time. By integrating the velocity function, we can find the total area under the curve, which gives us the displacement.
Conclusion:
The area under the velocity-time curve between times t1 and t2 represents the displacement of the object during that interval of time. This is because integration of the velocity function gives us the total area under the curve, which represents the change in displacement.
In a distance - time graph, motion of two cars A & B is plotted in the form of a Straight line. If the line on the graph is steeper for A as compared to B, What can you infer from the graph?- a)Speed of A is greater than speed of B
- b)Distance travelled by A is greater than distance travelled by B
- c)Speed of B is greater than speed of A
- d)Distance travelled by B is greater than distance travelled by A
Correct answer is option 'A'. Can you explain this answer?
In a distance - time graph, motion of two cars A & B is plotted in the form of a Straight line. If the line on the graph is steeper for A as compared to B, What can you infer from the graph?
a)
Speed of A is greater than speed of B
b)
Distance travelled by A is greater than distance travelled by B
c)
Speed of B is greater than speed of A
d)
Distance travelled by B is greater than distance travelled by A
 | Akanksha Menon answered |
Understanding the Distance-Time Graph
In a distance-time graph, the slope of the line represents the speed of the object. The steeper the slope, the greater the speed. Let's analyze the information given about cars A and B.
Key Observations
- The line representing car A is steeper than that of car B.
- This indicates that car A covers more distance in the same amount of time compared to car B.
Implications of a Steeper Line
- Speed Comparison: A steeper line corresponds to a higher speed. Since car A's line is steeper, it confirms that:
- Speed of A is greater than speed of B (Correct answer: option 'A').
- Distance Travelled: While the distance travelled can be inferred from the graph, the steepness specifically indicates speed rather than total distance. Both cars could have travelled the same distance if observed over a longer period, but the slope is a direct measure of their speeds at any given instant.
Conclusion
From the given graph, it is clear that:
- Speed of A is greater than speed of B.
Thus, option 'A' is the correct inference from the distance-time graph. Understanding the relationship between slope and speed is crucial in analyzing motion in physics.
In a distance-time graph, the slope of the line represents the speed of the object. The steeper the slope, the greater the speed. Let's analyze the information given about cars A and B.
Key Observations
- The line representing car A is steeper than that of car B.
- This indicates that car A covers more distance in the same amount of time compared to car B.
Implications of a Steeper Line
- Speed Comparison: A steeper line corresponds to a higher speed. Since car A's line is steeper, it confirms that:
- Speed of A is greater than speed of B (Correct answer: option 'A').
- Distance Travelled: While the distance travelled can be inferred from the graph, the steepness specifically indicates speed rather than total distance. Both cars could have travelled the same distance if observed over a longer period, but the slope is a direct measure of their speeds at any given instant.
Conclusion
From the given graph, it is clear that:
- Speed of A is greater than speed of B.
Thus, option 'A' is the correct inference from the distance-time graph. Understanding the relationship between slope and speed is crucial in analyzing motion in physics.
The distance traversed in first 10 sec is:
A gas has molecular formula (CH)n. If vapour density of the gas is 39, what should be the formula of the compound?- a)C3H3
- b)C4H4
- c)C2H2
- d)C6H6
Correct answer is option 'D'. Can you explain this answer?
A gas has molecular formula (CH)n. If vapour density of the gas is 39, what should be the formula of the compound?
a)
C3H3
b)
C4H4
c)
C2H2
d)
C6H6
| | Riya Banerjee answered |
Mol. wt. = 2 x V.D. = 2 x 39 = 78
(CH)n = (13)n or 13 x n = 78
n = 78/13 = 6
∴ Molecular formula = C6H6
(CH)n = (13)n or 13 x n = 78
n = 78/13 = 6
∴ Molecular formula = C6H6
Which of the following kingdoms has no well define boundaries?- a)Monera
- b)Protista
- c)Fungi
- d)Metaphyta and Metazoa
Correct answer is option 'B'. Can you explain this answer?
Which of the following kingdoms has no well define boundaries?
a)
Monera
b)
Protista
c)
Fungi
d)
Metaphyta and Metazoa
| | Mira Joshi answered |
Although all single-celled eukaryotes (except some unicellular algae e.g., Chlamydomonas, Chlorella etc., fungi e.g., Yeasta and animals, which are placed in their respective kingdoms along with their closely related multicellular organisms) are placed in kingdom Protista, yet its boundaries are not well defined.
In which of the following examples of motion, can the body be considered approximately a point object?- a)a railway carriage moving without jerks between two stations
- b)a spinning top moving on a curved path
- c)a tumbling beaker that has slipped off the edge of a table
- d)a spinning cricket ball that turns sharply on hitting the ground
Correct answer is option 'A'. Can you explain this answer?
In which of the following examples of motion, can the body be considered approximately a point object?
a)
a railway carriage moving without jerks between two stations
b)
a spinning top moving on a curved path
c)
a tumbling beaker that has slipped off the edge of a table
d)
a spinning cricket ball that turns sharply on hitting the ground
| | Jyoti Kapoor answered |
(a) The size of a carriage is very small as compared to the distance between two stations. Therefore, the carriage can be treated as a point sized object.
(c) The size of a beaker is comparable to the height of the table from which it slipped. Hence, the beaker cannot be considered as a point object.
(d) The size of a spinning cricket ball is comparable to the distance through which it turns sharply on hitting the ground. Hence, the cricket ball cannot be considered as a point object.
In Kinematics we study- a)Ways to find jerk without going into the causes of motion.
- b)Ways to describe motion without going into the causes of motion.
- c)Ways to find velocity without going into the causes of motion.
- d)Ways to find acceleration without going into the causes of motion.
Correct answer is option 'B'. Can you explain this answer?
In Kinematics we study
a)
Ways to find jerk without going into the causes of motion.
b)
Ways to describe motion without going into the causes of motion.
c)
Ways to find velocity without going into the causes of motion.
d)
Ways to find acceleration without going into the causes of motion.
 | Kalyan Desai answered |
Explanation:Kinematics is a branch of classical mechanics that describes the motion of points, bodies (objects), and systems of bodies (groups of objects) without considering the mass of each or the forces that caused the motion.
For motion in a straight line- a)motion away from origin is positive
- b)motion towards origin is positive
- c)position to the left of the origin is taken as positive and to the right as negative.
- d)position to the right of the origin is taken as positive and to the left as negative.
Correct answer is option 'D'. Can you explain this answer?
For motion in a straight line
a)
motion away from origin is positive
b)
motion towards origin is positive
c)
position to the left of the origin is taken as positive and to the right as negative.
d)
position to the right of the origin is taken as positive and to the left as negative.
 | Raghav Chakraborty answered |
Explanation:To describe motion along a straight line, we can choose an axis, say X-axis, so that it coincides with the path of the object. We then measure the position of the object with reference to a conveniently chosen origin, say O, Positions to the right of O are taken as positive and to the left of O, as negative.
For motion in 3 dimensions we need- a)No frame of reference is required ; a set of 3 points will do.
- b)Frame of reference consisting of a clock and a Cartesian coordinate system having two mutually perpendicular axes, labeled X-, and Y- axes
- c)Frame of reference consisting of a clock and a Cartesian coordinate system having three mutually perpendicular axes, labeled X-, Y-, and Z- axes
- d)No frame of reference is required a single point will do.
Correct answer is option 'C'. Can you explain this answer?
For motion in 3 dimensions we need
a)
No frame of reference is required ; a set of 3 points will do.
b)
Frame of reference consisting of a clock and a Cartesian coordinate system having two mutually perpendicular axes, labeled X-, and Y- axes
c)
Frame of reference consisting of a clock and a Cartesian coordinate system having three mutually perpendicular axes, labeled X-, Y-, and Z- axes
d)
No frame of reference is required a single point will do.
 | Uday Chakraborty answered |
Explanation:Motion is a change in position of an object with time. In order to specify position, we need to use a reference point and a set of axes. It is convenient to choose a rectangular coordinate system consisting of three mutually perpenducular axes, labelled X-, Y-, and Z- axes.
The point of intersection of these three axes is called origin (O) and serves as the reference point. The coordinates (x, y. z) of an object describe the position of the object with respect to this coordinate system.
To measure time, we position a clock in this system. This coordinate system along with a clock constitutes a frame of reference.
Slime moulds are- a)photosynthetic protists
- b)saprophytic protists
- c)both (a) and (b)
- d)none of these
Correct answer is option 'B'. Can you explain this answer?
Slime moulds are
a)
photosynthetic protists
b)
saprophytic protists
c)
both (a) and (b)
d)
none of these
 | Ayush Chatterjee answered |
Slime moulds as saprophytic protists
Slime moulds are categorized as saprophytic protists because they obtain their nutrients by decomposing organic matter. They play a crucial role in breaking down dead plant material, fungi, and bacteria in the environment. This decomposition process is essential for recycling nutrients back into the ecosystem.
Feeding mechanism of slime moulds
Slime moulds feed by engulfing their food source, which consists of bacteria, spores, and other organic material. They secrete enzymes to break down the organic matter into simpler compounds that can be absorbed by the organism. This process of decomposition helps in nutrient cycling and maintaining the balance of the ecosystem.
Life cycle of slime moulds
Slime moulds have a unique life cycle that involves two main stages: the vegetative stage and the reproductive stage. During the vegetative stage, the slime mould exists as a single-celled organism or a mass of cells. When conditions are favorable, they form spore-bearing structures for reproduction. These spores are dispersed into the environment, where they can germinate and start a new life cycle.
Ecological significance of slime moulds
Slime moulds play a crucial role in the ecosystem as decomposers, helping to break down dead organic matter and recycle nutrients. They contribute to the health of the environment by ensuring that essential nutrients are returned to the soil for use by plants and other organisms. Their feeding mechanism and life cycle help maintain the balance of the ecosystem and support biodiversity.
In conclusion, slime moulds are saprophytic protists that play a vital role in nutrient cycling and ecosystem health. Their feeding mechanism, life cycle, and ecological significance highlight their importance in maintaining a balanced and healthy environment.
Slime moulds are categorized as saprophytic protists because they obtain their nutrients by decomposing organic matter. They play a crucial role in breaking down dead plant material, fungi, and bacteria in the environment. This decomposition process is essential for recycling nutrients back into the ecosystem.
Feeding mechanism of slime moulds
Slime moulds feed by engulfing their food source, which consists of bacteria, spores, and other organic material. They secrete enzymes to break down the organic matter into simpler compounds that can be absorbed by the organism. This process of decomposition helps in nutrient cycling and maintaining the balance of the ecosystem.
Life cycle of slime moulds
Slime moulds have a unique life cycle that involves two main stages: the vegetative stage and the reproductive stage. During the vegetative stage, the slime mould exists as a single-celled organism or a mass of cells. When conditions are favorable, they form spore-bearing structures for reproduction. These spores are dispersed into the environment, where they can germinate and start a new life cycle.
Ecological significance of slime moulds
Slime moulds play a crucial role in the ecosystem as decomposers, helping to break down dead organic matter and recycle nutrients. They contribute to the health of the environment by ensuring that essential nutrients are returned to the soil for use by plants and other organisms. Their feeding mechanism and life cycle help maintain the balance of the ecosystem and support biodiversity.
In conclusion, slime moulds are saprophytic protists that play a vital role in nutrient cycling and ecosystem health. Their feeding mechanism, life cycle, and ecological significance highlight their importance in maintaining a balanced and healthy environment.
Causal organisms of sleeping sickness and kala-azar belong to which of the following groups of protozoan protists?- a)Amoeboid protozoans
- b)Flagellated protozoans
- c)Ciliated protozoans
- d)Sporozoans
Correct answer is option 'B'. Can you explain this answer?
Causal organisms of sleeping sickness and kala-azar belong to which of the following groups of protozoan protists?
a)
Amoeboid protozoans
b)
Flagellated protozoans
c)
Ciliated protozoans
d)
Sporozoans
| | Mira Joshi answered |
Trypanosom a gambiense, causes Gambian sleeping sickness. The parasite is transmitted by blood sucking tse-tse fly, Glossina palpalis. Leishmania donovani cause kala-azar or dum-dum fever (= visceral leishmaniasis). The parasite is transmitted by sandfly, Phlebotomus argentipes and other species. Causal organisms of bloth diseases belong to flagellated protozoans of kingdom Protista.
A truck is coming towards you from a distance of 1000m on a straight road, at time t=0. It reaches you in 100sec. The average speed in m/s is- a)14
- b)10
- c)17
- d)12
Correct answer is option 'B'. Can you explain this answer?
A truck is coming towards you from a distance of 1000m on a straight road, at time t=0. It reaches you in 100sec. The average speed in m/s is
a)
14
b)
10
c)
17
d)
12
| | Sinjini Shah answered |
Given information:
Distance of truck from observer = 1000 m
Time taken by truck to reach observer = 100 s
To find: Average speed of truck in m/s
Formula used:
Average speed = Total distance/Total time
Calculation:
Total distance covered by truck = 1000 m
Total time taken by truck to cover the distance = 100 s
Using the formula of average speed:
Average speed = Total distance/Total time
= 1000 m/100 s
= 10 m/s
Therefore, the average speed of the truck is 10 m/s.
Answer: Option (b) 10.
Distance of truck from observer = 1000 m
Time taken by truck to reach observer = 100 s
To find: Average speed of truck in m/s
Formula used:
Average speed = Total distance/Total time
Calculation:
Total distance covered by truck = 1000 m
Total time taken by truck to cover the distance = 100 s
Using the formula of average speed:
Average speed = Total distance/Total time
= 1000 m/100 s
= 10 m/s
Therefore, the average speed of the truck is 10 m/s.
Answer: Option (b) 10.
Which out of the following is a ciliated protozoan?- a)Plasmodium vivax
- b)Amoeba proteus
- c)Paramoecium caudalum
- d)Leishmania donovani
Correct answer is option 'C'. Can you explain this answer?
Which out of the following is a ciliated protozoan?
a)
Plasmodium vivax
b)
Amoeba proteus
c)
Paramoecium caudalum
d)
Leishmania donovani
| | Mira Joshi answered |
Paramoecium is a free living ciliate which is found in fresh water. Most widely distributed species are Paramoecium caudatum and Paramoecium aurelia. The, cilia of the extreme posterior end are longer and form a bunch called caudal tuft.
A truck covers 40.0 m in 8.50 s while smoothly slowing down to a final speed of 2.80 m/s. Find its original speed in m/s
- a)6.61
- b)5.61
- c)7.61
- d)8.61
Correct answer is option 'A'. Can you explain this answer?
A truck covers 40.0 m in 8.50 s while smoothly slowing down to a final speed of 2.80 m/s. Find its original speed in m/s
a)
6.61
b)
5.61
c)
7.61
d)
8.61
 | Anjana Sharma answered |
v=v0+at
2.8=v0+8.5a--->1
x=v0t+1/2at^2
40=8.5v0+1/2a(8.5)^2 --2
Solve 1 and 2
v0 = 2.8-8.5a
40=8.5v0 +36.1a
40=8.5(2.8-8.5a) +36.1a
40=23.8-72.3a +36.1a
36.2a = -16.2
a = -0.448m/s^2
Substitute a value in v0 equation.
v0 = 2.8-8.5( -0.448m/s^2)
v0 = 6.61 m/sec
The percentage composition of oxygen in water (H2O) is:- a)11.11%
- b)88.89%
- c)16.00%
- d)50.00%
Correct answer is option 'B'. Can you explain this answer?
The percentage composition of oxygen in water (H2O) is:
a)
11.11%
b)
88.89%
c)
16.00%
d)
50.00%
 | EduRev NEET answered |
The correct answer is Option B - 88.89%
Take atomic masses: hydrogen = 1 u and oxygen = 16 u.
Molar mass of H2O = 2 × 1 + 16 = 18 g/mol.
Mass of oxygen in one mole of H2O = 16 g.
Percentage of oxygen = (16 ÷ 18) × 100 = 88.888...% ≈ 88.89%.
Therefore the percentage of oxygen in water is 88.89%.
With reference to the figure which shows a particle moving along a straight line , y axis represents the position and x axis represents time, if x1 = 18m, The average velocity at if x1 in m/s is
- a)180
- b)1.8
- c)18
- d)20
Correct answer is option 'C'. Can you explain this answer?
With reference to the figure which shows a particle moving along a straight line , y axis represents the position and x axis represents time, if x1 = 18m, The average velocity at if x1 in m/s is
a)
180
b)
1.8
c)
18
d)
20
| | Pooja Kulkarni answered |
Explanation:
Average velocity can be defined as the displacement divided by the time.
Total displacement d = 18 m
Time taken t = 1 s
Assertion (A): Percentage composition helps in determining empirical formula of a compound. Reason (R): Empirical formula represents simplest whole number ratio of atoms in a compound.- a)Both A and R are true and R is the correct explanation of A
- b)Both A and R are true but R is not the correct explanation of A
- c)A is true but R is false
- d)A is false but R is true
Correct answer is option 'A'. Can you explain this answer?
a)
Both A and R are true and R is the correct explanation of A
b)
Both A and R are true but R is not the correct explanation of A
c)
A is true but R is false
d)
A is false but R is true
 | Infinity Academy answered |
Correct Option - A
The correct answer is Option A - Both A and R are true and R is the correct explanation of A
Percentage composition gives the relative mass percentages of each element in a compound, which provides the mass of each element present in a chosen sample size.
To find the empirical formula one typically assumes a 100 g sample so that each percentage becomes the mass in grams of that element; each mass is then divided by the element's atomic mass to obtain the number of moles of that element.
Those mole values are converted into the simplest whole-number proportions by dividing all mole amounts by the smallest mole value to get the mole ratio; if needed, the ratio is multiplied by a small integer to yield whole numbers.
Empirical formula is defined as the simplest whole-number ratio of atoms of the elements in a compound.
Because percentage composition leads directly to relative masses, then to moles, and finally to the mole ratio, the reason given correctly explains why percentage composition is useful for determining the empirical formula.
Match each item in Column I with one in Column II and select your answer from the codes given below:
- a) A-b, B-a, C-d, D-c
- b) A-b, B-d, C-a, D-c
- c)A-b, B-d, C-c, D-a
- d)A-d, B-c, C-a, D-b
Correct answer is option 'B'. Can you explain this answer?
Match each item in Column I with one in Column II and select your answer from the codes given below:
a)
A-b, B-a, C-d, D-c
b)
A-b, B-d, C-a, D-c
c)
A-b, B-d, C-c, D-a
d)
A-d, B-c, C-a, D-b
| | Top Rankers answered |
- Diatoms (A) have a cell wall that is embedded with silica, giving them a rigid structure. This makes the correct match A-b.
- Dinoflagellates (B) have cellulose plates in their cell walls, which are characteristic of this group, often leading to their description as having "armored" cells. This makes the correct match B-d.
- Euglenoids (C) do not have a traditional cell wall; instead, they have a flexible outer layer known as a pellicle, which is a protein-rich layer. This makes the correct match C-a.
- Slime moulds (D) are known for producing spores that have true walls, used in their reproductive cycle. This makes the correct match D-c.
A compound contains 27.27% carbon and 72.73% oxygen. Its empirical formula is:- a)CO
- b)CO₂
- c)C₂O₃
- d)C₃O₄
Correct answer is option 'B'. Can you explain this answer?
a)
CO
b)
CO₂
c)
C₂O₃
d)
C₃O₄
 | Dr. Mohit Rajpoot answered |
The correct answer is Option B - CO₂
Take a 100 g sample so that the masses are 27.27 g of carbon and 72.73 g of oxygen.
Moles of carbon = 27.27 ÷ 12 = 2.2725. Moles of oxygen = 72.73 ÷ 16 = 4.5456.
Divide both mole values by the smallest mole number 2.2725 to obtain the simplest whole-number ratio: carbon = 1, oxygen = 2.
Thus the empirical formula is CO₂.
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