MCQOPTIONS
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MCQOPTIONS
This section includes 12583 Mcqs, each offering curated multiple-choice questions to sharpen your Joint Entrance Exam - Main (JEE Main) knowledge and support exam preparation. Choose a topic below to get started.
| 851. |
The value of \[\hat{i}\,\times \,(\hat{i}\times \,\vec{a})\,+\hat{j}\,\times \,(\hat{j}+\vec{a})\,+\hat{k}+(\,\hat{k}\times \hat{a})\] is |
| A. | \[\vec{a}\] |
| B. | \[\vec{a}\,\times \,\hat{k}\] |
| C. | \[-2\vec{a}\] |
| D. | \[-\,\vec{a}\] |
| Answer» D. \[-\,\vec{a}\] | |
| 852. |
For constructive interference to take place between two monochromatic light waves of wavelength l, the path difference should be [MNR 1992; UPSEAT 2001] |
| A. | \[(2n-1)\frac{\lambda }{4}\] |
| B. | \[(2n-1)\frac{\lambda }{2}\] |
| C. | \[n\lambda \] |
| D. | \[(2n+1)\frac{\lambda }{2}\] |
| Answer» D. \[(2n+1)\frac{\lambda }{2}\] | |
| 853. |
Colours of thin films result from [CPMT 1972, 83, 96; RPMT 1997; DCE 2002; AIIMS 2005] or On a rainy day, a small oil film on water show brilliant colours. This is due to [MP PET 2004] |
| A. | Dispersion of light |
| B. | Interference of light |
| C. | Absorption of light |
| D. | Scattering of light |
| Answer» C. Absorption of light | |
| 854. |
If the overbridge is concave instead of being convex, the thrust on the road at the lowest position will be |
| A. | \[mg+\frac{m{{v}^{2}}}{r}\] |
| B. | \[mg-\frac{m{{v}^{2}}}{r}\] |
| C. | \[\frac{{{m}^{2}}{{v}^{2}}g}{r}\] |
| D. | \[\frac{{{v}^{2}}g}{r}\] |
| Answer» B. \[mg-\frac{m{{v}^{2}}}{r}\] | |
| 855. |
The value of Poisson's ratio lies between [AIIMS 1985; MP PET 1986; DPMT 2002] |
| A. | ?1 to \[\frac{1}{2}\] |
| B. | \[-\frac{3}{4}\] to \[-\frac{1}{2}\] |
| C. | \[-\frac{1}{2}\] to 1 |
| D. | 1 to 2 |
| Answer» B. \[-\frac{3}{4}\] to \[-\frac{1}{2}\] | |
| 856. |
Assertion : The cloud in sky generally appear to be whitish. Reason : Diffraction due to clouds is efficient in equal measure at all wavelengths. [AIIMS 2005] |
| A. | If both assertion and reason are true and the reason is the correct explanation of the assertion. |
| B. | If both assertion and reason are true but reason is not the correct explanation of the assertion. |
| C. | If assertion is true but reason is false. |
| D. | If the assertion and reason both are false. |
| E. | If assertion is false but reason is true. |
| Answer» D. If the assertion and reason both are false. | |
| 857. |
Assertion : It is necessary to use satellites for long distance T.V. transmission. Reason : The television signals are low frequency signals. |
| A. | If both assertion and reason are true and the reason is the correct explanation of the assertion. |
| B. | If both assertion and reason are true but reason is not the correct explanation of the assertion. |
| C. | If assertion is true but reason is false. |
| D. | If the assertion and reason both are false. |
| E. | If assertion is false but reason is true. |
| Answer» D. If the assertion and reason both are false. | |
| 858. |
Assertion : Television signals are received through sky-wave propagation. Reason : The ionosphere reflects electromagnetic waves of frequencies greater than a certain critical frequency. [AIIMS 2005] |
| A. | If both assertion and reason are true and the reason is the correct explanation of the assertion. |
| B. | If both assertion and reason are true but reason is not the correct explanation of the assertion. |
| C. | If assertion is true but reason is false. |
| D. | If the assertion and reason both are false. |
| E. | If assertion is false but reason is true. |
| Answer» E. If assertion is false but reason is true. | |
| 859. |
An object is kept on a smooth inclined plane of 1 in \[l\]. The horizontal acceleration to be imparted to the inclined plane so that object is stationary relative to the incline is given by |
| A. | \[g({{l}^{2}}-1)\] |
| B. | \[g({{l}^{2}}-1)\] |
| C. | \[\frac{g}{\sqrt{{{l}^{2}}-1}}\] |
| D. | \[\frac{g}{{{l}^{2}}-l}\] |
| Answer» D. \[\frac{g}{{{l}^{2}}-l}\] | |
| 860. |
In case of uniform circular motion which of the following physical quantity do not remain constant [Kerala PMT 2004] |
| A. | Speed |
| B. | Momentum |
| C. | Kinetic energy |
| D. | Mass |
| Answer» C. Kinetic energy | |
| 861. |
A transistor is connected in common -emitter configuration. The collector supply is \[8\,V\] and the voltage drop across a resistor of \[800\,W\] in the collector is \[0.5\text{ }V\]. If the current gain factor \[\alpha \] is\[0.96\]. Find the base current. |
| A. | \[26\,\mu A\] |
| B. | \[16\,\mu A\] |
| C. | \[10\,\mu A\] |
| D. | \[5\,\mu A\] |
| Answer» B. \[16\,\mu A\] | |
| 862. |
Two long parallel wires P and Q are both perpendicular to the plane of the paper with distance 5 m between them. If P and Q carry current of 2.5 amp and 5 amp respectively in the same direction, then the magnetic field at a point half way between the wires is [Kerala PMT 2005] |
| A. | \[\frac{\sqrt{3}{{\mu }_{0}}}{2\pi }\] |
| B. | \[\frac{{{\mu }_{0}}}{\pi }\] |
| C. | \[\frac{3{{\mu }_{0}}}{2\pi }\] |
| D. | \[\frac{{{\mu }_{0}}}{2\pi }\] |
| E. | (e) \[\frac{\sqrt{3}{{\mu }_{0}}}{\pi }\] |
| Answer» E. (e) \[\frac{\sqrt{3}{{\mu }_{0}}}{\pi }\] | |
| 863. |
Assertion : The dominant mechanism for motion of charge carriers in forward and reverse biased silicon P-N junction are drift in both forward and reverse bias. Reason : In reverse biasing, no current flow through the junction. |
| A. | If both assertion and reason are true and the reason is the correct explanation of the assertion. |
| B. | If both assertion and reason are true but reason is not the correct explanation of the assertion. |
| C. | If assertion is true but reason is false. |
| D. | If the assertion and reason both are false. |
| E. | If assertion is false but reason is true. |
| Answer» E. If assertion is false but reason is true. | |
| 864. |
Assertion : In transistor common emitter mode as an amplifier is preferred over common base mode. Reason : In common emitter mode the input signal is connected in series with the voltage applied to the base emitter function. |
| A. | If both assertion and reason are true and the reason is the correct explanation of the assertion. |
| B. | If both assertion and reason are true but reason is not the correct explanation of the assertion. |
| C. | If assertion is true but reason is false. |
| D. | If the assertion and reason both are false. |
| E. | If assertion is false but reason is true. |
| Answer» C. If assertion is true but reason is false. | |
| 865. |
Assertion : A transistor is a voltage-operating device. Reason : Base current is greater than the collector current. |
| A. | If both assertion and reason are true and the reason is the correct explanation of the assertion. |
| B. | If both assertion and reason are true but reason is not the correct explanation of the assertion. |
| C. | If assertion is true but reason is false. |
| D. | If the assertion and reason both are false. |
| E. | If assertion is false but reason is true. |
| Answer» E. If assertion is false but reason is true. | |
| 866. |
An iron ball of mass m, suspended by a light inextensible string of length from a fixed point, 0, is shifted by an angle \[{{\theta }_{0}}\] as shown so as to strike the vertical wall perpendicularly. The ' maximum angle made by the string with vertical after the first collision, if e is the coefficient of restitution, is |
| A. | \[{{\sin }^{-1}}\left\{ 1-{{e}^{2}}\left( 1-\cos {{\theta }_{0}} \right) \right\}\] |
| B. | \[{{\cos }^{-1}}\left\{ 1-{{e}^{2}}\left( 1-\cos {{\theta }_{0}} \right) \right\}\] |
| C. | \[{{\tan }^{-1}}\left\{ 1-{{e}^{2}}\left( 1-\cos {{\theta }_{0}} \right) \right\}\] |
| D. | Zero |
| Answer» C. \[{{\tan }^{-1}}\left\{ 1-{{e}^{2}}\left( 1-\cos {{\theta }_{0}} \right) \right\}\] | |
| 867. |
What will be the force constant of the spring system shown in figure? |
| A. | \[\frac{{{k}_{1}}}{2}+{{k}_{2}}\] |
| B. | \[{{\left[ \frac{1}{2{{k}_{1}}}+\frac{1}{{{k}_{2}}} \right]}^{-1}}\] |
| C. | \[\left[ \frac{1}{2{{k}_{1}}}+\frac{1}{{{k}_{2}}} \right]\] |
| D. | \[{{\left[ \frac{2}{{{k}_{1}}}+\frac{1}{{{k}_{2}}} \right]}^{-1}}\] |
| Answer» C. \[\left[ \frac{1}{2{{k}_{1}}}+\frac{1}{{{k}_{2}}} \right]\] | |
| 868. |
A pan with set of weights is attached with a light spring. When disturbed, the mass-spring system oscillates with a time period of 0.6 s. When some additional weights are added then time period is 0.7s. The extension caused by the additional weights is approximately given by [UPSEAT 2002] |
| A. | 1.38 cm |
| B. | 3.5 cm |
| C. | 1.75 cm |
| D. | 2.45 cm |
| Answer» C. 1.75 cm | |
| 869. |
The energy gap of silicon is 1.14 eV. The maximum wavelength at which silicon will begin absorbing energy is [MP PMT 1993] |
| A. | 10888 Å |
| B. | 1088.8 Å |
| C. | 108.88 Å |
| D. | 10.888 Å |
| Answer» B. 1088.8 Å | |
| 870. |
The displacement of an object "attached to a spring and executing simple harmonic motion is given by \[x=2\times {{10}^{-2\,\,\,}}\cos \,\pi t\] metre. The time at which the maximum speed first occurs is |
| A. | 0.25s |
| B. | 0.5s |
| C. | 0.75s |
| D. | 0.125s |
| Answer» C. 0.75s | |
| 871. |
A wind-powered generator converts wind energy into electrical energy. Assume that the generator converts a fixed fraction of the wind energy intercepted by its blades into electrical energy For wind speed v, the electrical power output will be proportional to |
| A. | v |
| B. | \[{{v}^{2}}\] |
| C. | \[{{v}^{3}}\] |
| D. | \[{{v}^{4}}\] |
| Answer» D. \[{{v}^{4}}\] | |
| 872. |
Assertion : The average and instantaneous velocities have same value in a uniform motion. Reason : In uniform motion, the velocity of an object increases uniformly. |
| A. | If both assertion and reason are true and the reason is the correct explanation of the assertion. |
| B. | If both assertion and reason are true but reason is not the correct explanation of the assertion. |
| C. | If assertion is true but reason is false. |
| D. | If the assertion and reason both are false. |
| E. | If assertion is false but reason is true. |
| Answer» D. If the assertion and reason both are false. | |
| 873. |
Assertion : In the process of photoelectric emission, all the emitted photoelectrons have the same kinetic energy. Reason : The photon transfers its whole energy to the electron of the atom in photoelectric effect. |
| A. | If both assertion and reason are true and the reason is the correct explanation of the assertion. |
| B. | If both assertion and reason are true but reason is not the correct explanation of the assertion. |
| C. | If assertion is true but reason is false. |
| D. | If the assertion and reason both are false. |
| E. | If assertion is false but reason is true. |
| Answer» F. | |
| 874. |
Masses of two substances are 1 g and 9 g respectively. If their kinetic energies are same, then the ratio of their momentum will be [BHU 2004] |
| A. | 1 : 9 |
| B. | 9 : 1 |
| C. | 3 : 1 |
| D. | 1 : 3 |
| Answer» E. | |
| 875. |
1 g of a steam at 100°C melt how much ice at 0°C? (Latent heat of ice = 80 cal/gm and latent heat of steam = 540 cal/gm) [Pb. PET 2000] |
| A. | 1 gm |
| B. | 2 gm |
| C. | 4 gm |
| D. | 8 gm |
| Answer» E. | |
| 876. |
Assertion : The work done during a round trip is always zero. Reason : No force is required to move a body in its round trip. |
| A. | If both assertion and reason are true and the reason is the correct explanation of the assertion. |
| B. | If both assertion and reason are true but reason is not the correct explanation of the assertion. |
| C. | If assertion is true but reason is false. |
| D. | If the assertion and reason both are false. |
| E. | If assertion is false but reason is true. |
| Answer» E. If assertion is false but reason is true. | |
| 877. |
A reactor converts 100% of given mass into energy and that it operates at a power of \[9\times {{10}^{7}}\] watt. The mass of the fuel consumed in 30 min in the reactor will be: |
| A. | \[12\times {{10}^{-3}}kg\] |
| B. | \[25\times {{10}^{-8}}kg\] |
| C. | \[18\times {{10}^{-7}}kg\] |
| D. | \[11\times {{10}^{-4}}kg\] |
| Answer» D. \[11\times {{10}^{-4}}kg\] | |
| 878. |
A thin slice is cut out of a glass cylinder along a plane parallel to its axis. The slice is placed on a flat glass plate as shown in Figure. The observed interference fringes from this combination shall be |
| A. | straight |
| B. | circular |
| C. | equally spaced |
| D. | having fringe spacing which increases as we go outwards |
| Answer» B. circular | |
| 879. |
For fission of uranium \[_{95}^{235}U\], one needs |
| A. | very fast neutrons (a few electrons volts) |
| B. | low energy neutrons (\[\approx \]0.04 eV at 300K) |
| C. | a moderator making neutrons slow |
| D. | both and |
| Answer» E. | |
| 880. |
When subjected to a transverse electric field, cathode rays move [MP PET 1994] |
| A. | Down the potential gradient |
| B. | Up the potential gradient |
| C. | Along a hyperbolic path |
| D. | Along a circular path |
| Answer» C. Along a hyperbolic path | |
| 881. |
Assertion : Multiplying any vector by an scalar is a meaningful operations. Reason : In uniform motion speed remains constant. |
| A. | If both assertion and reason are true and the reason is the correct explanation of the assertion. |
| B. | If both assertion and reason are true but reason is not the correct explanation of the assertion. |
| C. | If assertion is true but reason is false. |
| D. | If the assertion and reason both are false. |
| E. | If assertion is false but reason is true. |
| Answer» C. If assertion is true but reason is false. | |
| 882. |
Kinetic energy with which the electrons are emitted from the metal surface due to photoelectric effect is |
| A. | Independent of the intensity of illumination |
| B. | Independent of the frequency of light |
| C. | Inversely proportional to the intensity of illumination |
| D. | Directly proportional to the intensity of illumination |
| Answer» B. Independent of the frequency of light | |
| 883. |
The ratio of the coefficient of volume expansion of a glass container to that of a viscous liquid kept inside the container is 1 : 4. What fraction of the inner volume of the container should the liquid occupy so that the volume of the remaining vacant space will be same.at all temperatures? |
| A. | 0.0868055555555556 |
| B. | 0.0444444444444444 |
| C. | 0.0861111111111111 |
| D. | 0.0472222222222222 |
| Answer» C. 0.0861111111111111 | |
| 884. |
The mutual inductance between a primary and secondary circuits is 0.5 H. The resistances of the primary and the secondary circuits are 20 ohms and 5 ohms respectively. To generate a current of 0.4 A in the secondary, current in the primary must be changed at the rate of [MP PMT 1997] |
| A. | 4.0 A/s |
| B. | 16.0 A/s |
| C. | 1.6 A/s |
| D. | 8.0 A/s |
| Answer» B. 16.0 A/s | |
| 885. |
Energy stored in a coil of self inductance 40mH carrying a steady current of 2 A is [Kerala (Engg.) 2001] |
| A. | 0.8 J |
| B. | 8 J |
| C. | 0.08 J |
| D. | 80 J |
| Answer» D. 80 J | |
| 886. |
The amount of work done in blowing a soap bubble such that its diameter increases from d to D is (T= surface tension of the solution) [MP PMT 1996] |
| A. | \[4\pi ({{D}^{2}}-{{d}^{2}})T\] |
| B. | \[8\pi ({{D}^{2}}-{{d}^{2}})T\] |
| C. | \[\pi ({{D}^{2}}-{{d}^{2}})T\] |
| D. | \[2\pi ({{D}^{2}}-{{d}^{2}})T\] |
| Answer» E. | |
| 887. |
The isothermal bulk modulus of a gas at atmospheric pressure is [AIIMS 2000; KCET 1999; Pb. PMT 2003] |
| A. | \[1\,mm\]of Hg |
| B. | \[13.6\,mm\]of Hg |
| C. | \[1.013\times {{10}^{5}}\,N/{{m}^{2}}\] |
| D. | \[2.026\times {{10}^{5}}N/{{m}^{2}}\] |
| Answer» D. \[2.026\times {{10}^{5}}N/{{m}^{2}}\] | |
| 888. |
The spring balance does not read properly after its long use, because |
| A. | The elasticity of spring increases |
| B. | The elasticity decreases |
| C. | Its plastic power decreases |
| D. | Its plastic power increases |
| Answer» C. Its plastic power decreases | |
| 889. |
Assertion : The ion cannot move with a speed beyond a certain limit in a cyclotron. Reason : As velocity increases time taken by ion increases. |
| A. | If both assertion and reason are true and the reason is the correct explanation of the assertion. |
| B. | If both assertion and reason are true but reason is not the correct explanation of the assertion. |
| C. | If assertion is true but reason is false. |
| D. | If the assertion and reason both are false. |
| E. | If assertion is false but reason is true. |
| Answer» D. If the assertion and reason both are false. | |
| 890. |
In a plane progressive harmonic wave particle speed is always less than the wave speed if |
| A. | amplitude of wave is less than \[\frac{\lambda }{2\pi }\] |
| B. | amplitude of wave is greater than\[\frac{\lambda }{2\pi }\] |
| C. | amplitude of wave is less than \[\lambda \] |
| D. | amplitude of wave is greater than\[\frac{\lambda }{\pi }\] |
| Answer» B. amplitude of wave is greater than\[\frac{\lambda }{2\pi }\] | |
| 891. |
An e.m.f. of 5 volt is produced by a self inductance, when the current changes at a steady rate from 3 A to 2 A in 1 millisecond. The value of self inductance is [CPMT 1982; MP PMT 1991; CBSE PMT 1993; AFMC 2002] |
| A. | Zero |
| B. | 5 H |
| C. | 5000 H |
| D. | 5 mH |
| Answer» E. | |
| 892. |
The ratio of electrostatic and gravitational forces acting between electron and proton separated by a distance \[5\times {{10}^{-11}}m,\] will be (Charge on electron \[=\text{ 1}.\text{6}\times \text{1}{{0}^{\text{19}}}C\], mass of electron \[=\text{ 9}.\text{1}\times \text{1}{{0}^{\text{31}}}kg\], mass of proton = \[1.6\times {{10}^{-27}}kg,\] \[\,G=6.7\times {{10}^{-11}}\,N{{m}^{2}}/k{{g}^{2}})\] [RPET 1997; Pb PMT 2003] |
| A. | \[\text{2}.\text{36}\times \text{1}{{0}^{\text{39}}}\] |
| B. | \[\text{2}.\text{36}\times \text{1}{{0}^{40}}\] |
| C. | \[\text{2}.\text{34}\times \text{1}{{0}^{41}}\] |
| D. | \[\text{2}.\text{34}\times \text{1}{{0}^{42}}\] |
| Answer» B. \[\text{2}.\text{36}\times \text{1}{{0}^{40}}\] | |
| 893. |
Moment of inertia of a circular wire of mass M and radius R about its diameter is |
| A. | \[M{{R}^{2}}/2\] |
| B. | \[M{{R}^{2}}\] |
| C. | \[2M{{R}^{2}}\] |
| D. | \[M{{R}^{2}}/4\] |
| Answer» B. \[M{{R}^{2}}\] | |
| 894. |
On doping germanium with donor atoms of density \[{{10}^{17}}\,c{{m}^{-3}}\] its conductivity in mho/cm will be [Given \[{{\mu }_{e}}=3800\,c{{m}^{2}}V-s\] and \[{{n}_{i}}=2.5\times {{10}^{13}}c{{m}^{-13}}\]] |
| A. | \[30.4\] |
| B. | \[60.8\] |
| C. | \[91.2\] |
| D. | \[121.6\] |
| Answer» C. \[91.2\] | |
| 895. |
The velocity of a particle depends upon as \[v=a+bt+c{{t}^{2}}\]; if the velocity is in \[m/\sec \], the unit of \[a\] will be [CPMT 1990] |
| A. | \[m/\sec \] |
| B. | \[m/{{\sec }^{2}}\] |
| C. | \[{{m}^{2}}/\sec \] |
| D. | \[m/{{\sec }^{3}}\] |
| Answer» B. \[m/{{\sec }^{2}}\] | |
| 896. |
An insulated container of gas has two chambers separated by an insulating partition. One of the chambers has volume \[{{V}_{1}}\] and contains ideal gas at pressure \[{{P}_{1}}\], and temperature \[{{T}_{1}}\] The other chamber has volume \[{{V}_{2}}\] and contains ideal gas at pressure \[{{P}_{2}}\] and temperature \[{{T}_{2}}\] If the partition is removed without doing any work on the gas, the final equilibrium temperature of the gas in the container will be |
| A. | \[\frac{{{T}_{1}}{{T}_{2}}\left( {{P}_{1}}{{V}_{1}}+{{P}_{2}}{{V}_{2}} \right)}{{{P}_{1}}{{V}_{1}}+{{P}_{2}}{{V}_{2}}}\] |
| B. | \[\frac{{{P}_{1}}{{V}_{1}}{{T}_{1}}+{{P}_{2}}{{V}_{2}}{{T}_{2}}}{{{P}_{1}}{{V}_{1}}+{{P}_{2}}{{V}_{2}}}\] |
| C. | \[\frac{{{P}_{1}}{{V}_{1}}{{T}_{2}}+{{P}_{2}}{{V}_{2}}{{T}_{1}}}{{{P}_{1}}{{V}_{1}}+{{P}_{2}}{{V}_{2}}}\] |
| D. | \[\frac{{{T}_{1}}{{T}_{2}}\left( {{P}_{1}}{{V}_{1}}+{{P}_{2}}{{V}_{2}} \right)}{{{P}_{1}}{{V}_{1}}{{T}_{1}}+{{P}_{2}}{{V}_{2}}{{T}_{2}}}\] |
| Answer» B. \[\frac{{{P}_{1}}{{V}_{1}}{{T}_{1}}+{{P}_{2}}{{V}_{2}}{{T}_{2}}}{{{P}_{1}}{{V}_{1}}+{{P}_{2}}{{V}_{2}}}\] | |
| 897. |
A sound source emits frequency of 180 Hz when moving towards a rigid wall with speed 5 m/s and an observer is moving away from wall with speed 5 m/s. Both source and observer moves on a straight line which is perpendicular to the wall. The number of beats per second heard by the observer will be [Speed of sound = 355 m/s] |
| A. | 5 beats/s |
| B. | 10 beats/s |
| C. | 6 beats/s |
| D. | 8 beats/s |
| Answer» B. 10 beats/s | |
| 898. |
Assertion : Electric lines of force cross each other. Reason : Electric field at a point superimpose to give one resultant electric field. [AIIMS 1995] |
| A. | If both assertion and reason are true and the reason is the correct explanation of the assertion. |
| B. | If both assertion and reason are true but reason is not the correct explanation of the assertion. |
| C. | If assertion is true but reason is false. |
| D. | If the assertion and reason both are false. |
| E. | If assertion is false but reason is true. |
| Answer» F. | |
| 899. |
A thermoelectric refrigerator works on [JIPMER 2002] |
| A. | Joule effect |
| B. | Seeback effect |
| C. | Peltier effect |
| D. | Thermonic emission |
| Answer» D. Thermonic emission | |
| 900. |
An ionic atom equivalent to hydrogen atom has wavelength equal to 1/4 of the wavelengths of hydrogen lines. The ion will be [RPET 1997] |
| A. | \[H{{e}^{+}}\] |
| B. | \[L{{i}^{++}}\] |
| C. | \[N{{e}^{9+}}\] |
| D. | \[N{{a}^{10+}}\] |
| Answer» B. \[L{{i}^{++}}\] | |