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NEET Practice Test - 8 - NEET MCQ


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30 Questions MCQ Test - NEET Practice Test - 8

NEET Practice Test - 8 for NEET 2024 is part of NEET preparation. The NEET Practice Test - 8 questions and answers have been prepared according to the NEET exam syllabus.The NEET Practice Test - 8 MCQs are made for NEET 2024 Exam. Find important definitions, questions, notes, meanings, examples, exercises, MCQs and online tests for NEET Practice Test - 8 below.
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NEET Practice Test - 8 - Question 1

The velocity-time (v-t) graph for a moving object is shown in the figure. The total displacement of the object during the time interval when there is non-zero acceleration and retardation is

Detailed Solution for NEET Practice Test - 8 - Question 1
Between time interval 20 s to 40 s, there is non-zero acceleration and retardation.

Hence, distance travelled during this interval = Area under v-t graph between time interval 20 s to 40 s

= 1/2 × 20 × 3 + 20 × 1 = 30 + 20 = 50 m

NEET Practice Test - 8 - Question 2

Read the assertion and reason carefully to mark the correct option out of the options given below:

Assertion : The velocity of flow of a liquid is smaller when pressure is larger and viceversa.

Reason : According to Bernoulli's theorem, for the stream line flow of an ideal liquid, the total energy per unit mass remains constant.

Detailed Solution for NEET Practice Test - 8 - Question 2
According to Bernoulli's theorem, P + 1/2 Pv2 = a constant i.e. when velocity is large, the pressure is less in a stream line flow of an ideal liquid through a horizontal tube.
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NEET Practice Test - 8 - Question 3

A projectile can have the same range 'R' for two angles of projection. If T1 and T2 are the time durations of flights in the two cases, the product of T1 and T2 will be directly proportional to

Detailed Solution for NEET Practice Test - 8 - Question 3

Let the angles of projection be

NEET Practice Test - 8 - Question 4

The ratio of the accelerations for a solid sphere (mass m and radius R) rolling down an incline of angle without slipping and slipping down the incline without rolling is

Detailed Solution for NEET Practice Test - 8 - Question 4
A solid sphere rolling without slipping down an inclined plane

In this Case,

For solid sphere, k2 = (2/5)R2

For a sphere slipping down an inclined plane,

a2 = g sinθ

= 5 : 7

NEET Practice Test - 8 - Question 5

The radius of an air bubble at the bottom of a lake is 'r' and it becomes '2r' when the air bubble rises to the top surface of the lake. If 'P' cm of water is the atmospheric pressure, what is the depth of the lake?

Detailed Solution for NEET Practice Test - 8 - Question 5

Let depth of lake is x cm.

∴ P1V1 = P2V2

(P + x) r3 = P(8r3)

x = 8P - P

⇒ x = 7P

NEET Practice Test - 8 - Question 6

Two identical charges (Q each) are separated by a certain distance. A third charge q is placed on the line joining the two charges, such that all the three charges are in equilibrium. What is the magnitude of the third charge?

Detailed Solution for NEET Practice Test - 8 - Question 6
Suppose the charge q is placed somewhere between the two charges.

For equilibrium of charge q, resultant force on q should be zero.

r1 = r2 = r

So, the charge q should be placed midway between the two charges.

For equilibrium of the system, resultant force on each charge is zero.

So, the resultant force on Q = 0

Magnitude of the charge q = Q/4

NEET Practice Test - 8 - Question 7

Two circular coils 1 and 2 are made from the same wire, but the radius of the 1st coil is twice that of the 2nd coil. What is the ratio of potential differences applied across them, so that the magnetic field at their centres is the same?

Detailed Solution for NEET Practice Test - 8 - Question 7

B1 = B2

For resistances of coils

= 2 × 2 = 4

or V1 : V2 :: 4 : 1

NEET Practice Test - 8 - Question 8

A pendulum bob has a speed of 3 m/s at its lowest position. The pendulum is 0.5 m long. The speed of the bob, when length makes an angle of 60o to the vertical, is:

Detailed Solution for NEET Practice Test - 8 - Question 8

Potential energy of the bob at point B

PE = mg(l - l cosθ)

From law of conservation of energy, we have

Total energy at point A = total energy at point B

9 = v2 + 2gl(1 - cos60°)

v2 = 4 m/s

∴ v = 2 m/s

NEET Practice Test - 8 - Question 9

An eye specialist prescribes spectacles having a combination of a convex lens of focal length 40 cm in contact with a concave lens of focal length 25 cm. The power of this lens' combination is

Detailed Solution for NEET Practice Test - 8 - Question 9
Power of the lens combination is

which is choice (b).

NEET Practice Test - 8 - Question 10

If the input and output resistances in a common-base amplifier circuit are 400Ω and 400 kΩ, respectively, what is the collector current when the emitter current is 2 mA and current gain α is 0.98?

Detailed Solution for NEET Practice Test - 8 - Question 10
As

α = Ic / Ie

Ic = αIe

Ie = 2 mA,

α = 0.98

Ic = 1.96 mA

NEET Practice Test - 8 - Question 11

Which energy state of triply ionised beryllium (Be+++) has the same electron orbital radius as that of the ground state of hydrogen? Given Z for beryllium = 4.

Detailed Solution for NEET Practice Test - 8 - Question 11
For an atom of atomic number Z, the radius of the nth orbit is given by

where K = is a constant.

For the ground state of hydrogen (Z = 1), n = 1 so that r1 = K

Let n be the energy state of Be+++ for which the orbital radius is r1.

Putting Z = 4 and rn = r1 = K is Eq.

(i) we get

or n2 = 4 or n = 2

NEET Practice Test - 8 - Question 12

Two masses m1 = 6 kg and m2 = 4 kg are connected by means of a string which passes over a frictionless pulley as shown in the figure.

When the masses are released, what is the acceleration of the masses? (Take g = 10 ms-2)

Detailed Solution for NEET Practice Test - 8 - Question 12
The common acceleration of the masses is

Hence, the correct choice is (a).

NEET Practice Test - 8 - Question 13

A body moving in a straight line with constant acceleration of 10 ms-2 covers a distance of 40 m in the 4th second. How much distance will it cover in the 6th second?

Detailed Solution for NEET Practice Test - 8 - Question 13
The distance covered in the nth second is given by

or 40 = u + 7/2 × 10 or u = 40 - 35

= 5 ms-1

which gives S6 = 60 m

Thus, the correct answer is option (b).

NEET Practice Test - 8 - Question 14

A tube, closed at one end containing air, produces, when excited, the fundamental note of frequency 512 Hz. If the tube is open at both ends, then the fundamental frequency that can be excited will be (in Hz)

Detailed Solution for NEET Practice Test - 8 - Question 14

For a closed tube,

For an ipen tube,

Hence v’ = 2v = 2 x 512 = 1024 Hz

Thus the correct choice is (a)

NEET Practice Test - 8 - Question 15

Column-I gives certain physical terms associated with flow of current through a metallic conductor.

Column-II gives some mathematical relations involving electrical quantities.

Match Column-I and Column-II with appropriate relations.

Detailed Solution for NEET Practice Test - 8 - Question 15
Step 1: Find the formula of each quantity.

(A) Velocity,

(B) J = σE

J = E/ρ

Electrical resistivity ρ = E/J

(C)

Relaxation time,

(D) i = neAvd

Current density, J = i / A = nevd

Hence, the correct option is (c).

NEET Practice Test - 8 - Question 16

Consider the following statements (A) and (B) and identify the correct answer.

A. A zener diode is connected in reverse bias when used as a voltage regulator.

B. The potential barrier of p-n junction lies between 0.2 V to 0.3 V.

Detailed Solution for NEET Practice Test - 8 - Question 16
Recall the concept of the voltage regulator.

(A) Zener diode operate under reverse bias in the breakdown region and is used as a voltage regulator.

(B) The potential barrier can be between (0.6 to 0.7 ) V.

NEET Practice Test - 8 - Question 17

A proton of mass m and charge +e is moving in a circular orbit in a magnetic field with energy 1 MeV. What should be the energy of an α - particle (mass 4m and charge +2e) so that it revolves in a circular orbit of the same radius in the same magnetic field?

Detailed Solution for NEET Practice Test - 8 - Question 17

Here ‘r’ and ‘ B’ are constants

⇒ Kα = 1 MeV.

NEET Practice Test - 8 - Question 18

The graph between magnetic susceptibility and absolute temperature for a paramagnetic substance is

Detailed Solution for NEET Practice Test - 8 - Question 18

NEET Practice Test - 8 - Question 19

At a certain place on earth, the true angle of dip is 60°, if the dip circle is oriented at an angle of 45º with the magnetic meridian, then the apparent angle of dip shown by the dip circle will be

Detailed Solution for NEET Practice Test - 8 - Question 19

NEET Practice Test - 8 - Question 20

A transformer with a power efficiency of 80% converts a 10 V primary input voltage (with a current of 10 A) to a voltage of 20 V. The current in the secondary coil will be

Detailed Solution for NEET Practice Test - 8 - Question 20

Pout = ղPin

i = 4 A

NEET Practice Test - 8 - Question 21

A Daniel cell is connected to the primary coil of a transformer. If the output voltage of the Daniel cell is 10 V, and the ratio of secondary to primary coil turns of transformer is 2, then the voltage in the secondary will be

Detailed Solution for NEET Practice Test - 8 - Question 21
Transformer does not work for DC.
NEET Practice Test - 8 - Question 22

The average value of current i = (4t2) A from t = 0 to t = 4 s is

Detailed Solution for NEET Practice Test - 8 - Question 22

NEET Practice Test - 8 - Question 23

An AC generator’s coil has 2000 turns and is rotated with angular speed of 500 rad/s. If the area of the coil is 10 cm2 and the magnetic field is 0.2 T, then the peak voltage in the coil will be

Detailed Solution for NEET Practice Test - 8 - Question 23

Vmax = NBAω

= 2000 × 0.2 × 10 × 10–4 × 500

= 200 V

NEET Practice Test - 8 - Question 24

The impedance of the following circuit at very high frequencies of source voltage between A and B, will be

Detailed Solution for NEET Practice Test - 8 - Question 24
At very high frequencies of the source voltage, the inductor would behave as an open circuit and the capacitor would have like a conducting wire.

Rnet = R + R = 2R

NEET Practice Test - 8 - Question 25

When 100 V DC is applied across a solenoid, a current of 1 A flows in it. When 100 V AC is applied across the same coil, the current drops to 0.5 A. If the frequency of the AC source is 50 Hz, the impedance and inductance of the inductor for the given AC circuit are

Detailed Solution for NEET Practice Test - 8 - Question 25

For DC,

For AC,

⇒ L = 0.55H

NEET Practice Test - 8 - Question 26

The power factor of the circuit shown in the figure is

Detailed Solution for NEET Practice Test - 8 - Question 26

NEET Practice Test - 8 - Question 27

Consider the following two statements.

Statement-A: A hot wire ammeter reads the RMS value of current.

Statement-B: A hot wire ammeter can read AC but cannot read DC.

The correct statement(s) is/are

Detailed Solution for NEET Practice Test - 8 - Question 27
A hot wire instrument reads RMS values of both AC and DC.
NEET Practice Test - 8 - Question 28

The ratio of respective capacitive reactance when connected with a source of frequency 40 Hz and 60 Hz is

Detailed Solution for NEET Practice Test - 8 - Question 28

NEET Practice Test - 8 - Question 29

The network shown in the figure is part of a complete circuit. If at a certain instant, the current i is 5 A and decreasing at a rate of 103 As−1 then potential difference between A and B (VB−VA ) is equal to 

Detailed Solution for NEET Practice Test - 8 - Question 29

VA−5+15+5=VB
⇒VB−VA=15 V

NEET Practice Test - 8 - Question 30

An AC circuit having supply voltage V, consists of resistor of resistance 4 and capacitor of reactance 3 as shown in the figure. The voltage across the capacitor at time t = π / ωs is

Detailed Solution for NEET Practice Test - 8 - Question 30

= 12 V

As in capacitor current leads voltage.

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