In the following question, a Statement of Assertion (A) is given followed by a corresponding Reason (R) just below it. Read the Statements carefully and mark the correct answer-
Assertion(A): Electrical resistivity of typical insulator (≃ 1014Ω-m) is about 1022 times that of metal (≃ 10-8Ω-m) while in case of heat it is only about 103 (as KAg ≃ 400 W/mk while Kglass ≃ 1 W/mk)
Reason(R): In electrical conduction only free electrons take part while in thermal conduction both lattice and free electrons contribute.
A is the correct option.In electrical conduction only free electrons take part while in thermal conduction both lattice and free electrons contribute and this is the reason that leads to the phenomenon of Electrical resistivity of typical insulator (≃ 1014Ω-m) is about 1022 times that of metal (≃ 10-8Ω-m) while in case of heat it is only about 103 (as KAg ≃ 400 W/mk while Kglass ≃ 1 W/mk).
In the following question, a Statement of Assertion (A) is given followed by a corresponding Reason (R) just below it. Read the Statements carefully and mark the correct answer-
Assertion(A): It is easier to start a car engine on a warm day than cold day.
Reason(R): Internal energy of the engine is high on a warm day than a cold day .
The correct option is Option C.
It is easier to start a car engine on a warm day than on a chilly day. With increase in temperature (i.e., on a warm day) the internal resistance of a car battery decreases. Due to it, the battery can supply large current which helps in starting the car engine easily.
In the following question, a Statement of Assertion (A) is given followed by a corresponding Reason (R) just below it. Read the Statements carefully and mark the correct answer-
Assertion(A): Pressure in a bubble (σ) in an atmosphere of pressure P0 is where r is the radius.
Reason(R): is the excess pressure due to two surfaces exposed to the atmosphere.
The correct answer is B as both the given assertion and reason are true but reason is not the correct explanation of given assertion.as The excess pressure across a soap bubble of radius r is p=r4σ, where σ is the surface tension of soap solution.
Voltage in the secondary coil of a transformer does not depend upon.
The closest distance of approach of an α - particle travelling with a velocity 'V' to a certain nucleus is 'x'. The distance of closest approach of α - particle travelling with a velocity 3V to the same nucleus is
A 10 μF capacitor and a 20 μF capacitor are connected in series across 200 V supply line. The charged capacitors are then disconnected from the line and reconnected with their positive plates together and negative plates together and no external voltage is applied. What is the potential difference across each capacitor?
C1 = 10μF, C2 = 20μF
Fquivalent capacitance in series
Charge on each capacitor
q = CV
In seies charge in both capacitor is same.
∴ toal charge
Now the capacitors are connected in parallel.
Equivalent capacitance in parallel.
Potential
If the de Broglie wavelengths for a proton and for a α-particle are equal, then the ratio of their velocities will be
Two solid rubber balls A and B having masses 200 and 400 gm respectively are moving in opposite directions with velocity A equal to 0.3 m/s. After collision the two balls come to rest, then the velocity of B is
You are given several identical resistances each of value R = 10 Ω and each capable of carrying maximum current of 1 ampere. It is required to make a suitable combination of these resistances to produce a resistance of 5Ω which can carry a current of 4 amperes. The minimum number of resistances of the type R that will be required for this job
An electron and a proton have the same de-Broglie wavelength. Then the kinetic energy of the electron is
If intensity of incident light is increased in PEE then which of the following is true
According to Einstein's photoelectric equation, the plot of the kinetic energy of the emitted photoelectrons from a metal versus frequency of the incident radiation gives a straight line, whose slope
The working of a dynamo is based on principle of
A 100 mH coil carries a current of 10 A. The magnetic energy stored in the coil is
A coil of inductances 300mH and resistance 2 Ω is connected to a source of voltage 2V. The current reaches half of its steady state value in
Which of the following statement is true?
A straight wire of length l and electric dipole moment p is bent to from a semicircle. The new electric dipole moment would be
A cylinder of radius r and length a is placed in a uniform in a uniform electric field E parallel to the axis of the cylinder. The total electric flux over the curved surface of cylinder is
The electric flux entering and leaving the cylindrical surface is same
Φ = EπR2 - EπR2 = 0
where, E = electric field
R = radius of cylinder
Φ = outward flux
In an L-R circuit, the value of L is (0.4/π) henry and the value of R is 30 ohm. If in the circuit, an alternating emf of 200 volt at 50 cycles per second is connected, the impedance of the circuit and current will be
The enegy stored in wound watch spring is
A car travelling at a speed of 30 km/hr is brought to a halt in 8 m by applying brakes. If the same car is travelling at 60 km/hr, it can be brought to a halt with the same braking force in
The rate of transfer of heat is more in
Time taken by a 846 W heater to heat one litre of water from 10ºC to 40ºC is
Two similar bar magnets P and Q each of magnetic moment M are taken. If P is cut along its axial line and Q is cut along its equatorial line, all the four pieces obtained have each of
A bar magnet, of magnetic moment M, is placed in a magnetic field of induction B. The torque exerted on it is
Two wires of the same material and length, but diameters in the ratio 1 : 2 are stretched by the same force. The elastic potential energy stored per unit volume for the two wires when stretched, will be in the ratio of
The ratio of the weight of a man in a stationary lift and when it is moving downward with uniform acceleration 'a' is 3:2. The value of 'a' is (g-Acceleration due to gravity of the earth)
Half life of a radioactive substance which disintegrates by 75% in 60 minutes will be
If a spring is extended to length l, then according to Hooke's law
In the following question, a Statement of Assertion (A) is given followed by a corresponding Reason (R) just below it. Read the Statements carefully and mark the correct answer-
Assertion(A): We use a thick wire in the secondary of a step down transformer to reduce the production of heat.
Reason(R): When the plane of the armature is parallel to the line of force of magnetic field, the magnitude of the induced emf is maximum.
In the following question, a Statement of Assertion (A) is given followed by a corresponding Reason (R) just below it. Read the Statements carefully and mark the correct answer-
Assertion(A): Efficiency of an engine with sink temperature of zero Kelvin is 100%.
Reason(R): Keeping the sink at ice point with the source at 100oC will bring 100% efficiency.
In the following question, a Statement of Assertion (A) is given followed by a corresponding Reason (R) just below it. Read the Statements carefully and mark the correct answer-
Assertion(A): Potential energy is defined for only conservative forces.
Reason(R):
In the following question, a Statement of Assertion (A) is given followed by a corresponding Reason (R) just below it. Read the Statements carefully and mark the correct answer-
Assertion(A): Energy output in a fusion reaction is very much less than energy released in the fission process.
Reason(R): Fusion is a weaker energy-source than fission.
The energy output in a fusion reaction (21.6 MeV) is very much less than the energy released in the fission of a U235 nucleus (190 MeV). But this does not mean that fusion is a weaker energy source than fission. The number of hydrogen nuclei in 1 gram of heavy hydrogen is much larger than the number of U235 nuclei in 1 gram of uranium. Therefore, the energy obtained by the fusion of a certain mass of heavy hydrogen is much larger than tje energy obtained by the fission of equal mass of uranium
In the following question, a Statement of Assertion (A) is given followed by a corresponding Reason (R) just below it. Read the Statements carefully and mark the correct answer-
Assertion(A): The magnetic field at the ends of a very long current carrying solenoid is half of that at the centre.
Reason(R): If the solenoid is sufficiently long, the field within it is uniform.
In the following question, a Statement of Assertion (A) is given followed by a corresponding Reason (R) just below it. Read the Statements carefully and mark the correct answer-
Assertion(A): At the same temperature, the speed of sound in oxygen is one-fourth the speed of sound in hydrogen.
Reason(R): Molecular weight of oxygen is more than the molecular weight of hydrogen .
In the following question, a Statement of Assertion (A) is given followed by a corresponding Reason (R) just below it. Read the Statements carefully and mark the correct answer-
Assertion(A): X-rays and γ-rays are similar in many aspects.
Reason(R): X-rays and γ-rays have the same sources of origin.
In the following question, a Statement of Assertion (A) is given followed by a corresponding Reason (R) just below it. Read the Statements carefully and mark the correct answer-
Assertion(A): A charged particle moves perpendicular to magnetic field. Its kinetic energy remains constant, but momentum changes.
Reason(R): Force acts perpendicular to velocity of the particle.
In the following question, a Statement of Assertion (A) is given followed by a corresponding Reason (R) just below it. Read the Statements carefully and mark the correct answer-
Assertion(A): Thermistor is a device to detect small change in temperature.
Reason(R): The magnitude of the temperature coefficient of resistivity is often quite large for semiconducting material.
In the following question, a Statement of Assertion (A) is given followed by a corresponding Reason (R) just below it. Read the Statements carefully and mark the correct answer-
Assertion(A): The amplitude of an oscillating pendulum decreases with time.
Reason(R): The frequency also decreases with time.
In the following question, a Statement of Assertion (A) is given followed by a corresponding Reason (R) just below it. Read the Statements carefully and mark the correct answer-
Assertion(A): Study of Fraunhofer lines in the spectrum of sun led to the discovery of hydrogen.
Reason(R): Fraunhofer lines are dark lines in the continuous solar spectrum.
In the following question, a Statement of Assertion (A) is given followed by a corresponding Reason (R) just below it. Read the Statements carefully and mark the correct answer-
Assertion(A): Refractive index of a material depends on the frequency of the light
Reason(R): Incoming e.m. wave applies an electric field and polarises it, contributing to (∈) permittivity of the medium, depending on its frequency.
In the following question, a Statement of Assertion (A) is given followed by a corresponding Reason (R) just below it. Read the Statements carefully and mark the correct answer-
Assertion(A): The maximum frequency of the photon produced by the union of a positron and an electron is 1.2 x1020Hertz.
Reason(R): In electron-positron collision, both are annihilated and the total mass is converted into γ-photon(energy).
In the following question, a Statement of Assertion (A) is given followed by a corresponding Reason (R) just below it. Read the Statements carefully and mark the correct answer-
Assertion(A): Electron capture occurs more often than positron emission in heavy elements.
Reason(R): Heavy elements exhibit radioactivity.
In the following question, a Statement of Assertion (A) is given followed by a corresponding Reason (R) just below it. Read the Statements carefully and mark the correct answer-
Assertion(A): Frictional forces are conservative.
Reason(R): Potential energy can be associated with frictional forces.
In the following question, a Statement of Assertion (A) is given followed by a corresponding Reason (R) just below it. Read the Statements carefully and mark the correct answer-
Assertion(A): The SI unit of magnetic field is also known as Tesla
Reason(R): 1T = 1NA-1m-1
In the following question, a Statement of Assertion (A) is given followed by a corresponding Reason (R) just below it. Read the Statements carefully and mark the correct answer-
Assertion(A): Two parallel wires carrying current in the same direction attract each other.
Reason(R): Two similar charges moving parallel to each other in same direction repel each other.
An electric motor exerts a force of 40 N on a cable and pulls it by a distance of 30 m in one minute. The power supplied by the motor is
If the horizontal range of a projectile is equal to the maximum height reached, then the corresponding angle of projection is
Horizontal range = maximum height reached
The maximum energy received by the earth from the sun is in the form of
Under minimum deviation condition in a prism, if a ray is incident at an angle 30º , the angle between the emergent ray and the refracting surface of the prism is
The refracting angle of a prism A is small. The correct statement for the dispersive power of a prism is that dispersive power
The valency of an impurity added to germanium crystal in order to convert it into a P-type semi-conductor is
Zener breakdown in a semi-conductor diode occurs when
Which of the following does not make use of chemical effect of current?
The dimensions of Planck's constant and angular momentum are respectively
The unit of acceleration is a
In Huygen's wave theory, the locus of all points oscillating in the same phase is called a
A wave front travels
Ratio of intensities of two waves is given by 4 : 1. Then, ratio of the amplitudes of the two waves is
It is easier to draw up a wooden block along a inclined plane than to haul it vertically, principally because
Glycerol on heating with potassium bisulphate yields
The maximum amount of BaCl₄ precipitated on mixing BaCl₂ (0.5 M) with H₂SO₄ (1M) will correspond to
An organic compound contains 49.3% carbon, 6.84% hydrogen and its vapour density is 73. Molecular formula of compound is
The oxidation of toluene with air in the presence of V₂O₅ catalyst, gives
Which of the following possesses the highest melting point?
The size of C ― C bond in benzene, is
Water gas is a mixture of
In graphite, the electrons are
Which of the following species is paramagnetic?
A first order reaction is 50% complete in 10 minutes. The rate constant of the reaction is
Which of the following is true about catalyst?
Heat capacity is
In the following question, a Statement of Assertion (A) is given followed by a corresponding Reason (R) just below it. Read the Statements carefully and mark the correct answer-
Assertion(A): 10 vol. H₂O₂ means that 1 mL of H₂O₂ solution at NTP gives 10 mL of O₂ gas.
Reason(R): H₂O₂ decomposes to give water and O₂.
In the following question, a Statement of Assertion (A) is given followed by a corresponding Reason (R) just below it. Read the Statements carefully and mark the correct answer-
Assertion(A): In Ch3CH2CH2Cl; + I inductive effect in present.
Reason(R): Chlorine is more electronegative than carbon.
In the following question, a Statement of Assertion (A) is given followed by a corresponding Reason (R) just below it. Read the Statements carefully and mark the correct answer-
Assertion(A): Oxidation of amino-naphthalene yields phthalic acid.
Reason(R): An amino group attached to the benzene ring renders it sensitive to oxidation.
In the following question, a Statement of Assertion (A) is given followed by a corresponding Reason (R) just below it. Read the Statements carefully and mark the correct answer-
Assertion(A): In an acid-base titration involving strong base and a weak acid. methyl orange can be used as an indicator.
Reason(R): Methyl orange changes its colour in the pH range 3 to 5.
In the following question, a Statement of Assertion (A) is given followed by a corresponding Reason (R) just below it. Read the Statements carefully and mark the correct answer-
Assertion(A): S(N)1 mechanism is facilitated by polar protic solvents like water, alcohol etc.
Reason(R):C₆H₅CH(C₆H₅)−Br is less stable than C₆H₅CH(CH₃)Br in S(N)1 reactions.
In the following question, a Statement of Assertion (A) is given followed by a corresponding Reason (R) just below it. Read the Statements carefully and mark the correct answer-
Assertion(A): Urease is an enzyme which catalyses the hydrolysis of urea.
Reason(R): All catalysts are enzymes.
In the following question, a Statement of Assertion (A) is given followed by a corresponding Reason (R) just below it. Read the Statements carefully and mark the correct answer-
Assertion(A): KCl/NaCl/NH₄Cl etc. cannot be used in the salt bridge of a cell containing silver.
Reason(R): A salt bridge contains concentrated solution of an inert electrolyte like KCl, KNO₃, K₂SO₄ etc. or solidified solution of such an electrolyte in agar-agar and gelatine.
In the following question, a Statement of Assertion (A) is given followed by a corresponding Reason (R) just below it. Read the Statements carefully and mark the correct answer-
Assertion(A): Power alcohol is a mixture of petrol, benzene and alcohol.
Reason(R): Alcohol supports burning of petrol.
In the following question, a Statement of Assertion (A) is given followed by a corresponding Reason (R) just below it. Read the Statements carefully and mark the correct answer-
Assertion(A): Aqueous solution of Na₂CO₃ is alkaline in nature.
Reason(R): When dissolved in water, Na₂CO₃ undergoes anionic hydrolysis to form strong base and weak acid.
In the following question, a Statement of Assertion (A) is given followed by a corresponding Reason (R) just below it. Read the Statements carefully and mark the correct answer-
Assertion(A): Absorption spectrum consists of some bright lines separated by dark lines.
Reason(R): Emission spectrum consists of dark lines.
In the following question, a Statement of Assertion (A) is given followed by a corresponding Reason (R) just below it. Read the Statements carefully and mark the correct answer-
Assertion(A): H⁺ ion has a very high polarising power.
Reason(R): Size of H⁺ ion is very small.
In the following question, a Statement of Assertion (A) is given followed by a corresponding Reason (R) just below it. Read the Statements carefully and mark the correct answer-
Assertion(A): Potash alum is used in purification of water.
Reason(R): Potash alum is able to precipitate colloidal particles present in dirty water.
In the following question, a Statement of Assertion (A) is given followed by a corresponding Reason (R) just below it. Read the Statements carefully and mark the correct answer-
Assertion(A): Al(OH)3 is amphoteric in nature.
Reason(R): Al-O and O-H bonds can be broken with equal ease in Al(OH)3.
In the following question, a Statement of Assertion (A) is given followed by a corresponding Reason (R) just below it. Read the Statements carefully and mark the correct answer-
Assertion(A): Melting point of calcium halides decreases in the order CaI₂>CaBr₂>CaCl₂.
Reason(R): Smaller ions have lesser polarisability and thus their compounds are more ionic.
In the following question, a Statement of Assertion (A) is given followed by a corresponding Reason (R) just below it. Read the Statements carefully and mark the correct answer-
Assertion(A): Water is not known to react with metal salts.
Reason(R): Water occupies the interstitial sites in the crystal lattice of some compounds.
In the following question, a Statement of Assertion (A) is given followed by a corresponding Reason (R) just below it. Read the Statements carefully and mark the correct answer-
Assertion(A): Non-metals oxidation state of metal
Reason(R): Oxidation state of metal becomes positive as it is oxidised and non-metal becomes negative asitis reduced.
In the following question, a Statement of Assertion (A) is given followed by a corresponding Reason (R) just below it. Read the Statements carefully and mark the correct answer-
Assertion(A): Li resembles Mg.
Reason(R): Li⁺ has almost same size as Mg2⁺.
In the following question, a Statement of Assertion (A) is given followed by a corresponding Reason (R) just below it. Read the Statements carefully and mark the correct answer-
Assertion(A): White phosphorus is less stable than red phosphorus.
Reason(R): White phosphorus exists as P4 molecules.
In the following question, a Statement of Assertion (A) is given followed by a corresponding Reason (R) just below it. Read the Statements carefully and mark the correct answer-
Assertion(A): [Al(NH3)6]3+ does not exist in aqueous solution.
Reason(R): NH3 is a neutral ligand.
In the following question, a Statement of Assertion (A) is given followed by a corresponding Reason (R) just below it. Read the Statements carefully and mark the correct answer-
Assertion(A): Fluoroacetic acid is a stronger acid than chloroacetic acid.
Reason(R): Carboxylic acids are waeak acids and turn blue litmus red .
For measuring the conductivity of an electrolyte its solution should be prepared in
Solution of sodium metal in liquid ammonia is strongly reducing due to the presence in the solution of the following
At what temperature, the volume of a gas at 0ºC will become double, when pressure remains constant?
Which of the following compounds is used in gun powder?
The equivalent conductance of NaCl, HCl and C₂H₅COONa at infinite dilution are 126.45, 426.16 and 91 ohm⁻1 cm2 respectively. The eq. conductance of C₂H₅COOH is
Which of the following alkali metal ions has lowest ionic mobility in aqueous solution?
A chloride dissolves appreciably in cold water. When placed on a platinum wire in Bunsen flame no distinctive colour is noted, which cation would be present?
Chlorine acts as a bleaching agent only in the presence of
What happens when few drops of H₂SO₄ are added to water?
The process used for the removal of hardness of water is
If one drop of methyl orange is added in a solution, the solution becomes pink. The solution is
Identify the indicator used to titrate Na₂CO₃ solution with HCl
Hydrogen ion concentration of 0.2 M CH₃COOH, which is 40% dissociated, is
Which of the following reagents is used to distinguish acetone and acetophenone?
Which of the following compounds can react with the Lewis base Cl− in a Lewis acid-base reaction?
Benzophenone can be converted into benzene using
The addition of HBr to alkenes in the presence of peroxides is called :
Conc.HNO3 forms in presence of:
Which does not contain conjugate system?
In dienes, when the double bonds connected to each other by a single bond, this arrangement is known as conjugated.
Piezoelectric crystals are used in
Which of the following is the second most abundant element in the earth's crust?
Quartz is a crystalline variety of
At room temperature, the mole fraction of a solute is 0.25 and the vapour pressure of a solvent is 0.80 atm. Then the lowering of vapour pressure is
The process of osmosis was first discovered by
The volume of 0.1 M H₂SO₄ solution required to neutralise 50 ml of 0.2 M NaOH solution is
7 grams of CO on complete oxidation produce the following weight of CO2
Which of the following properties are not correct for enantiomers?
The valence shell of transition elements consist of
The outermost shealth of connective tissues, that surrounds a skeletal muscle, is
The skull of birds is
Trilobites evolved during
In the following question, a statement of Assertion(A) is given followed by a corresponding statement of Reason(R).
Read the statements carefully, and mark the correct answer.
Assertion(A): The final reabsorption of water from urine into blood occurs through the collecting duct of a mammalian nephron, resuliting in the production of hyperosmotic urine.
Reason(R): The loop of Henle is responsible for the formation of a sodium gradient across the depth of the cortical interstitium of a mammalian kidney.
The effect of collecting duct depends on the prescence of vasopressin. This hormone increases the permeability of the collecting duct to water. Gradually the rate of reabsorption from the filterate increases and it becomes hyperosmotic.
Loop of Henle is a U-shaped tubular part which lies in the renal medulla, which has a thin walled permeable descending limb and thick walled impermeable ascending limb.Na+, K+ and Cl- are transported out of thick segement of ascending limb.
In the following question, a Statement of Assertion (A) is given followed by a corresponding Reason(R) just below it.Read the Statement carefully and mark the correct answer-
Assertion(A): Ants generally disperse the fruits and seeds having oil bodies.
Reason (R): They feed on the oily substances.
In the following question, a Statement of Assertion (A) is given followed by a corresponding Reason(R) just below it.Read the Statement carefully and mark the correct answer-
Assertion(A): Cordate and obcordate both are heart-shaped leaves.
Reason (R): Cordate and obcordate are synonymous.
In the following question, a statement of Assertion(A) is given followed by a corresponding statement of Reason(R).
Read the statements carefully, and mark the correct answer.
Assertion(A): Meiotic division results in the production of four dissimilar cells.
Reason(R): Synapsis occurs during zygotene of meiosis.
Mitosis give rise to two daughter cells, which are identical to each other as well as to the parent cell.While, Meiosis is a double division which occurs in a diploid cell (or nucleus) and gives rise to four haploid cells (or nuclei), each having half the number of chromosomes as compared to the parent cell.Meiosis give rise to four daughter cells. These four cells, though resemble each other with respect to chromosome number, they differ, since paternal and maternal chromosomes would reassort during first division and these would give rise to new types due to exchange of chromosome segments. Synapsis occurs during zygotene of meiosis. The two homologous chromosomes get attached to each other, and the process of attachment is known as synapsis. It produces a complex known as synaptinemal complex.
In the following question, a Statement of Assertion (A) is given followed by a corresponding Reason(R) just below it.Read the Statement carefully and mark the correct answer-
Assertion(A): Primary cambium is a lateral meristem.
Reason (R): Cork cambium is the secondary meristem.
In the following question, a statement of Assertion(A) is given followed by a corresponding statement of Reason(R).
Read the statements carefully, and mark the correct answer.
Assertion(A): When the ambient temperature is high and soil contains excess of water, the plants tend to lose water in the form of droplets from lenticels.
Reason(R): Root pressure regulates the rate of loss of water form lenticels.
When the ambient temperature is high and soil contains excess water, the rate of transpiration is increased i.e. loss of water takes place from leaves through stomata.
Lenticular transpiration is only 0.1% of the total transpiration. It however continues day and night because lenticels have no mechanism of closure. The lenticels connect the atmospheric air with the cortical tissue of stem through intercellular spaces present amongst the complementary cells. Root pressure regulates the rate of loss of water from the stomata in some plants.
In the following question, a Statement of Assertion (A) is given followed by a corresponding Reason(R) just below it.Read the Statement carefully and mark the correct answer-
Assertion(A): An embryo is formed from the fertilized egg.
Reason (R): An embryo always contains an embryonal axis with two cotyledons.
In the following question, a Statement of Assertion (A) is given followed by a corresponding Reason(R) just below it.Read the Statement carefully and mark the correct answer-
Assertion(A): Cladodes are atems of unlimited growth.
Reason (R): Only the main stem is modified as cladodes.
In the following question, a Statement of Assertion (A) is given followed by a corresponding Reason(R) just below it.Read the Statement carefully and mark the correct answer-
Assertion(A): Collenchyma is dead cell.
Reason (R): Walls of collenchyma cells are completely thickened.
In the following question, a statement of Assertion(A) is given followed by a corresponding statement of Reason(R).
Read the statements carefully, and mark the correct answer.
Assertion(A): Presently, the global atmosphere is warming up.
Reason(R): The depletion of stratospheric ozone layer has resulted in increase in ultraviolet radiations reaching the earth.
The warming up of global atmosphere in the present day is ddue to the increase in green house effect.The greenhouse effect is the process by which absorption and emission of infrared radiation by gases in the atmosphere warm a planet's lower atmosphere and surface.
There is concern that increasing concentration of the green house gases including CO2, CH2 and man made chloroflurocarbons (CFCs), may enhance the green house effect and cause global warming. Ozone layer present in the stratosphere is depleted by the aerosols and chloroflurocarbonss.Ozone protects the earth from high energy ultra violet radiation.
In the following question, a statement of Assertion(A) is given followed by a corresponding statement of Reason(R).
Read the statements carefully, and mark the correct answer.
Assertion(A): Coconut tree is distributed in coastal areas over a large part of the world.
Reason(R): Coconut fruit can float and get dispersed over thousands of kilometers before losing viability.
Coconut tree is grown in coastal areas because it needs hot and wet climate. Coconut fruit show hydrochory i.e. the dispersal takes place through water medium. The coconut fruit is adopted the habitat of coastal areas, so the fruit can float and get dispersed over thousand of kelometers before losing viability.
In the following question, a statement of Assertion(A) is given followed by a corresponding statement of Reason(R).
Read the statements carefully, and mark the correct answer.
Assertion(A): Many visitor to the hills suffer from skin and respiratory allergy problems.
Reason(R): Conifer trees produce a large quantity of wind-borne pollen grains.
In hilly regions many trees like Oak, Elm, Hickory, Pecan and Cedar produce allergic pollen grains which cause allergy to people visiting the hills which results in the respiratory and skin problems.The symptoms of pollen allergy are- sneezing, itching eyes, nose and throat, dark circles under eyes caused by restricted blood flow near the sinuses, watering eyes and conjunctivitis.
Conifer trees produce a large quantity of wind borne pollen grains because many pollen grains are destroyed in the process of pollination done by wind.But these large number of pollen grains cause allergies.
In the following question, a Statement of Assertion (A) is given followed by a corresponding Reason(R) just below it.Read the Statement carefully and mark the correct answer-
Assertion(A): Plant roots absorb water from soil colloids.
Reason (R): Hygroscopic water is held by soil colloids.
In the following question, a statement of Assertion(A) is given followed by a corresponding statement of Reason(R).
Read the statements carefully, and mark the correct answer.
Assertion(A): Watson and Crick provided experimental proof of semiconservative nature of DNA replication.
Reason(R): DNA polymerase binds nucleotides in replication.
Watson and Crick suggested that replication of DNA is semiconservative.According to the semi Conservative mode each strand of the two double helices formed would have one old and one new strand.
While semiconservative nature of DNA replication was proved by Messelsn and Stahl by using heavy isotope of nitrogen (15N). DNA polymerase III establishes phosphodiester linkages between the adjacent deoxyribonucleodise phosphate in presence of ATP/GTP, TPP and Mg2+. It produces a new strand of DNA. DNA polymerase binds nucleotides in 5'-3' direction.
In the following question, a statement of Assertion(A) is given followed by a corresponding statement of Reason(R).
Read the statements carefully, and mark the correct answer.
Assertion(A): Inhabitants close to very busy airports are likely to experience health hazards.
Reason(R): Sound level of jet aeroplanes usually exceeds 160 dB.
Inhabitants close to very busy airports are likely to experience health hazards. Because maximum acceptable range of sound is 80 to 90 dB. But in the places like airports this level is always exceeds thus it creates sound pollution and related health hazards like auditory fatigue, deafness etc.
Jet planes generally produce sound above 160 dB which is much more than normal level, thus they also produce sound pollution. But as jet aeroplanes are used for some special purposes, they normally do not land in common airports. Thus it has no direct relation in causing sound pollution and related hazards in areas nearby very busy airports.
In the following question, a Statement of Assertion (A) is given followed by a corresponding Reason(R) just below it.Read the Statement carefully and mark the correct answer-
Assertion(A): In C3 plants, photosynthesis is reduced on high temperature.
Reason (R): C4 plants have high photosynthesis of high temperature.
In the following question, a Statement of Assertion (A) is given followed by a corresponding Reason(R) just below it.Read the Statement carefully and mark the correct answer-
Assertion(A): Shoot apex is protected by young buds.
Reason (R): Reproductive shoot apex is protected also by leaf primordia.
In the following questions, a statement of Assertion (A) is given followed by a corresponding Reason (R) just below it. Read the statements carefully and mark the answer-
Assertion (A): There are several types of chlorophylls.
Reason (R): Chlorophyll is an asymmetrical molecule.
In the following question, a statement of Assertion(A) is given followed by a corresponding statement of Reason(R).
Read the statements carefully, and mark the correct answer.
Assertion(A): Photomodulation of flowering is a phytochrome - regulated process.
Reason(R): Active form of phytochrome (Pfr) directly induces floral induction in shoot buds.
Flowering is a phytochrome regulated process.Phytochrome is a blue protein pigment with a molecular mass of about 125 kDa.Phytochrome occurs in two interconvertible forms PR which absorbs red light and PFR which absorbs far red light.
PFR is active form of phytochrome.When PR molecules are exposed to red light most of them absorb it and are then converted to PFR. This cnversion causes floral induction in the shoot.
In the following question, a statement of Assertion(A) is given followed by a corresponding statement of Reason(R).
Read the statements carefully, and mark the correct answer.
Assertion(A): The collenchyma is thick walled living tissue.
Reason(R): The collenchyma is thickened due to the deposition of pectin.
Collenchyma is a specialized type of parenchyma which is a supporting tissue. The cell walls are irregulary thickened due to the deposition of cellulose and pectin.
A condition called tachycardia exists when a person’s heart rate is abnormally high. Which of the following explains how tachycardia may arise?
Cellulose is
Which of these does not belong with the others?
Maximum calories are produced by-
The enamel of tooth is secreted by
Pesticides kill
International Rice Research Institute (IRRI) is located at
Cotton fibres are made up of
Duchenne's muscular dystrophy is a
The enzyme responsible for transcription is
Dryopithecus had
Reverse transcriptase is also known as
When the two genetic loci produce identical phenotypes in cis and trans position, they are considered to be
Surgical removal of thymus of a new born shall result in failure to produce
Bacteria which convert atmospheric nitrogen into nitrogen compounds are called
Antibody is connected with
AIDS spreads through
Salmonella causes
Edible part of Cauliflower is
Immunoglobin found in serum is
At a synapse, the neurotransmitters move to the receptor sites by
Rotation of crops is useful for
Which of the following compounds are widely distributed in both plants and animals?
Vascular bundles are absent in
A/c to option most preferable Ans is c Becoz vascular bundle is not well develope in pteridophyta so optionC is correct.
Who proved that oxygen envolved in photosynthesis comes from water?
In the two light reactions of photosynthesis
Some effects of sulphur dioxide and its transformation products on plant include