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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.
| 651. |
Assertion : In the phenomenon of mutual induction, self induction of each of the coils persists. Reason : Self induction arises when strength of current in same coil changes. In mutual induction, current is changing in both the individual coils. |
| 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. | |
| 652. |
The two ends of a conducting rod of varying cross. section are maintained at \[\text{20}{{\text{0}}^{\text{o}}}\text{C}\] and \[{{\text{0}}^{\text{o}}}\text{C}\] respectively in steady state |
| A. | temperature difference across AB is less than that of across CD |
| B. | temperature difference across AB is greater than of across CD |
| C. | temperature difference across AB is less than that of across CD |
| D. | temperature difference may be equal or different depending on the thermal conductivity |
| Answer» D. temperature difference may be equal or different depending on the thermal conductivity | |
| 653. |
A body starts from rest and acquires a velocity V in time T. The work done on the body in time t will be proportional to |
| A. | \[\frac{V}{T}t\] |
| B. | \[\frac{{{V}^{2}}}{T}{{t}^{2}}\] |
| C. | \[\frac{{{V}^{2}}}{{{T}^{2}}}t\] |
| D. | \[\frac{{{V}^{2}}}{{{T}^{2}}}{{t}^{2}}\] |
| Answer» E. | |
| 654. |
Assertion : Silicon is preferred over germanium for making semiconductor devices. Reason : The energy gap for germanium is more than the energy gap of silicon. |
| 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. | |
| 655. |
Assertion : We can measure the potential barrier of a PN junction by putting a sensitive voltmeter across its terminals. Reason : The current through the PN junction is not same in forward and reversed bias. |
| 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. | |
| 656. |
Two kg of water is converted into steam by boiling at atmospheric pressure. The volume changes from \[2\times {{10}^{-3}}{{m}^{3}}\] to \[3.34{{m}^{3}}.\]The work done by the system is about |
| A. | -340 kJ |
| B. | -170 kJ |
| C. | 170U kJ |
| D. | 340 kJ |
| Answer» E. | |
| 657. |
Find a vector of magnitude 5 along BA where coordinates of points A and B are (0, 1, 3) and (1, 4, 6) respectively |
| A. | \[\left( \frac{5}{\sqrt{19}} \right)[\hat{i}+3\hat{j}+3\hat{k}]\] |
| B. | \[-\left( \frac{5}{\sqrt{19}} \right)[\hat{i}+3\hat{j}+3\hat{k}]\] |
| C. | \[5[\hat{i}+3\hat{j}+3\hat{k}]\] |
| D. | \[-5[\hat{i}+3\hat{j}+3\hat{k}]\] |
| Answer» C. \[5[\hat{i}+3\hat{j}+3\hat{k}]\] | |
| 658. |
Given \[\vec{A}\,=\hat{i}+\hat{j}\,+\hat{k}\] and \[\vec{B}\,=-\hat{i}-\hat{j}-\hat{k},\,(\vec{A}-\vec{B})\] will make angle with \[\vec{A}\] as |
| A. | \[0{}^\circ \] |
| B. | \[{{180}^{o}}\] |
| C. | \[90{}^\circ \] |
| D. | \[60{}^\circ \] |
| Answer» B. \[{{180}^{o}}\] | |
| 659. |
\[\vec{A}-\vec{B}\] and \[\vec{A}\] are parallel. If \[|\vec{A}\times \vec{B}|\,=\,|\vec{A}.\vec{B}|,\] then angle between \[\vec{A}\] and \[\vec{B}\] will be |
| A. | \[30{}^\circ \] |
| B. | \[45{}^\circ \] |
| C. | \[60{}^\circ \] |
| D. | \[90{}^\circ \] |
| Answer» C. \[60{}^\circ \] | |
| 660. |
A scooter is going round a circular road of radius 100 m at a speed of 10 m/s. The angular speed of the scooter will be [Pb. PMT 2002] |
| A. | 0.01 rad/s |
| B. | 0.1 rad/s |
| C. | 1 rad/s |
| D. | 10 rad/s |
| Answer» C. 1 rad/s | |
| 661. |
Two vessels A and B contain water at temperature \[{{T}_{A}}\] and \[{{T}_{B}},\] at \[10{}^\circ C\] and \[2{}^\circ C\] respectively. If the water in both the vessels were compressed adiabatically and if we take into account the finite bulk modulus of elasticity of water, then \[{{T}_{A}}\] and \[{{T}_{B}}\] |
| A. | increase and decrease respectively |
| B. | decrease and increase respectively |
| C. | both increase |
| D. | both decrease |
| Answer» D. both decrease | |
| 662. |
When an ideal monoatomic gas is heated at constant pressure, the fraction of the heat energy supplied which increases the internal energy of the gas is |
| A. | 44318 |
| B. | 44319 |
| C. | 44380 |
| D. | 44382 |
| Answer» C. 44380 | |
| 663. |
Resistance \[R=V/I\], here \[V=(100\pm 5)\text{ }V\]and\[I=(10\pm 0.2)\text{ }A\]. Find percentage error in R. |
| A. | 0.05 |
| B. | 2% |
| C. | 7% |
| D. | 3% |
| Answer» D. 3% | |
| 664. |
The length of a simple pendulum is increased by 1%. Its time period will [MP PET 1994; RPET 2001] |
| A. | Increase by 1% |
| B. | Increase by 0.5% |
| C. | Decrease by 0.5% |
| D. | Increase by 2% |
| Answer» C. Decrease by 0.5% | |
| 665. |
A simple pendulum with a bob of mass ?m? oscillates from A to C and back to A such that PB is H. If the acceleration due to gravity is ?g?, then the velocity of the bob as it passes through B is [CBSE PMT 1995; DPMT 1995; Pb. PMT 1996] |
| A. | \[mgH\] |
| B. | \[\sqrt{2gH}\] |
| C. | \[T\frac{p-1}{p}\] |
| D. | Zero |
| Answer» C. \[T\frac{p-1}{p}\] | |
| 666. |
Identify correct statement among the following [Manipal MEE 1995] |
| A. | The greater the mass of a pendulum bob, the shorter is its frequency of oscillation |
| B. | A simple pendulum with a bob of mass M swings with an angular amplitude of \[{{40}^{o}}\]. When its angular amplitude is \[{{20}^{o}}\], the tension in the string is less than \[Mg\cos {{20}^{o}}\]. |
| C. | As the length of a simple pendulum is increased, the maximum velocity of its bob during its oscillation will also decreases |
| D. | The fractional change in the time period of a pendulum on changing the temperature is independent of the length of the pendulum |
| Answer» D. The fractional change in the time period of a pendulum on changing the temperature is independent of the length of the pendulum | |
| 667. |
Two objects P and Q initially at rest move towards each other under mutual force of attraction. At the instant when the velocity of P is v and that of Q is 2v, the velocity of centre of mass of the system is |
| A. | v |
| B. | 3v |
| C. | 2v |
| D. | zero |
| Answer» E. | |
| 668. |
DIRECTION: Read the passage given below and answer the questions that follows: A plane mirror \[({{M}_{1}})\] and a concave mirror \[({{M}_{2}})\] of focal length 10 cm are arranged as shown in figure. An object is kept at origin. Answer the following questions (Consider image formed by single reflection in all cases) The co-ordinates of image formed by the plane mirror are |
| A. | \[(-20\,cm,\,0)\] |
| B. | \[(10\,cm,\,-\,60\,cm)\] |
| C. | \[(10\,cm,\,-\,10\,cm)\] |
| D. | \[(10\,cm,\,\,10\,cm)\] |
| Answer» D. \[(10\,cm,\,\,10\,cm)\] | |
| 669. |
A person AB of height 170 cm is standing in front of a plane mirror. His eyes are at height 164 cm. At what distance from P should a hole be made in the mirror so that he cannot see the top of his head. |
| A. | 167 cm |
| B. | 161 cm |
| C. | 163 cm |
| D. | none of these |
| Answer» B. 161 cm | |
| 670. |
DIRECTION: Read the passage given below and answer the questions that follows: A plane mirror \[({{M}_{1}})\] and a concave mirror \[({{M}_{2}})\] of focal length 10 cm are arranged as shown in figure. An object is kept at origin. Answer the following questions (Consider image formed by single reflection in all cases) The co-ordinates of image formed by concave mirror are |
| A. | \[(10\,cm,\,\,-\,40\,cm)\] |
| B. | \[(10\,cm,\,\,-\,60\,cm)\] |
| C. | \[(10\,cm,\,\,8\,cm)\] |
| D. | None of these |
| Answer» E. | |
| 671. |
A long straight wire carries an electric current of 2A. The magnetic induction at a perpendicular distance of 5m from the wire is [EAMCET (Med.) 2000] |
| A. | \[4\times {{10}^{-8}}T\] |
| B. | \[8\times {{10}^{-8}}T\] |
| C. | \[12\times {{10}^{-8}}T\] |
| D. | \[16\times {{10}^{-8}}T\] |
| Answer» C. \[12\times {{10}^{-8}}T\] | |
| 672. |
A point mass oscillates along the x-axis according to the law\[x={{x}_{0}}\cos (\omega t-\pi /4)\]. If the acceleration of the particle is written as \[a=A\,\cos (\omega t+\delta )\], then |
| A. | \[A={{x}_{0}}{{\omega }^{2}},\,\delta =3\pi /4\] |
| B. | \[A={{x}_{0}},\,\delta =-\pi /4\] |
| C. | \[A={{x}_{0}}{{\omega }^{2}},\,\delta =\pi /4\] |
| D. | \[A={{x}_{0}}{{\omega }^{2}},\,\delta =-\pi /4\] |
| Answer» B. \[A={{x}_{0}},\,\delta =-\pi /4\] | |
| 673. |
A monoatomic gas molecule has |
| A. | Three degrees of freedom |
| B. | Four degrees of freedom |
| C. | Five degrees of freedom |
| D. | Six degrees of freedom |
| Answer» B. Four degrees of freedom | |
| 674. |
Two particles are oscillating along two close parallel straight lines side by side, with the same frequency and amplitudes. They pass each other, moving in opposite directions when their displacement is half of the amplitude. The mean positions of the two particles lie on a straight line perpendicular to the paths of the two particles. The phase difference |
| A. | 0 |
| B. | \[2\pi /3\] |
| C. | \[\pi \] |
| D. | \[\pi /6\] |
| Answer» C. \[\pi \] | |
| 675. |
Brilliance of diamond is due to [AIIMS 2002; MP PMT 2003] |
| A. | Shape |
| B. | Cutting |
| C. | Reflection |
| D. | Total internal reflection |
| Answer» E. | |
| 676. |
A light ray from air is incident (as shown in figure) at one end of a glass fiber (refractive index m = 1.5) making an incidence angle of 60o on the lateral surface, so that it undergoes a total internal reflection. How much time would it take to traverse the straight fiber of length 1 km [Orissa JEE 2002] |
| A. | 3.33 m sec |
| B. | 6.67 m sec |
| C. | 5.77 m sec |
| D. | 3.85 m sec |
| Answer» E. | |
| 677. |
Light wave enters from medium 1 to medium 2. Its velocity in 2nd medium is double from 1st. For total internal reflection the angle of incidence must be greater than [CPMT 2002] |
| A. | \[{{30}^{o}}\] |
| B. | \[{{60}^{o}}\] |
| C. | \[{{45}^{o}}\] |
| D. | \[{{90}^{o}}\] |
| Answer» B. \[{{60}^{o}}\] | |
| 678. |
A radioactive nucleus can decay by two different processes. The half-life for the first process is \[{{t}_{1}}\] and that for the second process is \[{{t}_{2}}\]. If effective half-life is t, then |
| A. | \[t={{t}_{1}}+{{t}_{2}}\] |
| B. | \[\frac{1}{t}=\frac{1}{{{t}_{1}}}+\frac{1}{{{t}_{2}}}\] |
| C. | \[t=\frac{2{{t}_{1}}{{t}_{2}}}{{{t}_{1}}+{{t}_{2}}}\] |
| D. | \[t=\frac{{{t}_{1}}+{{t}_{2}}}{2}\] |
| Answer» C. \[t=\frac{2{{t}_{1}}{{t}_{2}}}{{{t}_{1}}+{{t}_{2}}}\] | |
| 679. |
A particle is moving in a circle with uniform speed v. In moving from a point to another diametrically opposite point [Orissa JEE 2003] |
| A. | The momentum changes by mv |
| B. | The momentum changes by 2mv |
| C. | The kinetic energy changes by (1/2)mv2 |
| D. | The kinetic energy changes by mv2 |
| Answer» C. The kinetic energy changes by (1/2)mv2 | |
| 680. |
The magnetic moment of a current (i) carrying circular coil of radius (r) and number of turns (n) varies as [AIIMS 2004] |
| A. | 1/ r2 |
| B. | 1/ r |
| C. | r |
| D. | r2 |
| Answer» E. | |
| 681. |
If \[{{\lambda }_{\text{max}}}\] is 6563 Å, then wave length of second line for Balmer series will be [RPMT 2000] |
| A. | \[\lambda =\frac{16}{3R}\] |
| B. | \[\lambda =\frac{36}{5R}\] |
| C. | \[\lambda =\frac{4}{3R}\] |
| D. | None of the above |
| Answer» B. \[\lambda =\frac{36}{5R}\] | |
| 682. |
Which of the following is not represented in correct unit [NCERT 1984; MNR 1995] |
| A. | \[\frac{\text{Stress}}{\text{Strain}}=N/{{m}^{2}}\].... |
| B. | Surface tension =\[N/m\] |
| C. | Energy \[=kg\text{-}m/\sec \] |
| D. | Pressure \[=N/{{m}^{2}}\] |
| Answer» D. Pressure \[=N/{{m}^{2}}\] | |
| 683. |
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. | |
| 684. |
The energy band gap of \[Si\] is [MP PET 1994, 2002; BHU 1995; RPMT 2000] |
| A. | \[0.70\,eV\] |
| B. | 1.1 eV |
| C. | Between \[0.70\,eV\] to \[1.1\,eV\] |
| D. | 5 eV |
| Answer» C. Between \[0.70\,eV\] to \[1.1\,eV\] | |
| 685. |
Self-induction of a solenoid is [MP PMT 1993] |
| A. | Directly proportional to current flowing through the coil |
| B. | Directly proportional to its length |
| C. | Directly proportional to area of cross-section |
| D. | Inversely proportional to area of cross-section |
| Answer» D. Inversely proportional to area of cross-section | |
| 686. |
The wavelength of X-rays is [EAMCET (Med.) 1995] |
| A. | 2000 Å |
| B. | 2 Å |
| C. | 1 mm |
| D. | 1 cm |
| Answer» C. 1 mm | |
| 687. |
The unit of absolute permittivity is [CMEET Bihar 1995] |
| A. | \[Fm\] (Farad-meter) |
| B. | \[F{{m}^{-1}}\] (Farad/meter) |
| C. | \[F{{m}^{-2}}\](Farad/\[metr{{e}^{2}}\]) |
| D. | \[F\] (Farad) |
| E. | (e) None of these |
| Answer» C. \[F{{m}^{-2}}\](Farad/\[metr{{e}^{2}}\]) | |
| 688. |
Plate voltage of a triode is increased from 200 V to 225 V. To maintain the plate current, change in grid voltage from 5V to 5.75 V is needed. The amplification factor is [RPET 2002] |
| A. | 40 |
| B. | 45 |
| C. | 33.3 |
| D. | 25 |
| Answer» D. 25 | |
| 689. |
Fan is based on [AFMC 2003] |
| A. | Electric Motor |
| B. | Electric dynamo |
| C. | Both |
| D. | None of these |
| Answer» B. Electric dynamo | |
| 690. |
Assertion : If a proton and an a-particle enter a uniform magnetic field perpendicularly, with the same speed, then the time period of revolution of the a-particle is double than that of proton. Reason : In a magnetic field, the time period of revolution of a charged particle is directly proportional to mass. |
| 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. | |
| 691. |
A particle of mass m is attached to a spring (of spring constant k) and has a natural angular frequency\[{{\omega }_{0}}\]. An external force F (t) proportional to \[\cos \,\omega t(\omega \ne {{\omega }_{0}})\] is applied to the oscillator. The displacement of the oscillator will be proportional to |
| A. | \[\frac{1}{m(\omega _{0}^{2}+{{\omega }^{2}})}\] |
| B. | \[\frac{1}{m(\omega _{0}^{2}-{{\omega }^{2}})}\] |
| C. | \[\frac{m}{\omega _{0}^{2}-{{\omega }^{2}}}\] |
| D. | \[\frac{m}{(\omega _{0}^{2}+{{\omega }^{2}})}\] |
| Answer» C. \[\frac{m}{\omega _{0}^{2}-{{\omega }^{2}}}\] | |
| 692. |
The intensity of the central maximum in Young's double-slit experiment is 41. The intensity at the first minimum is zero and the distance between two consecutive maxima is w. The distance from the central maximum to the position where the intensity falls to I is |
| A. | \[\frac{2}{3}w\] |
| B. | \[\frac{1}{4}w\] |
| C. | \[\frac{1}{2}w\] |
| D. | \[\frac{1}{3}w\] |
| Answer» E. | |
| 693. |
Find the torque of a force \[\vec{F}=-3\hat{i}+\hat{j}+5\hat{k}\] acting at a point \[\vec{r}=7\hat{i}+3\hat{j}+\hat{k}\] |
| A. | \[14\hat{i}-38\hat{j}+16\hat{k}\] |
| B. | \[4\hat{i}+4\hat{j}+6\hat{k}\] |
| C. | \[21\hat{i}+4\hat{j}+4\hat{k}\] |
| D. | \[-14\hat{i}+34\hat{j}-16\hat{k}\] |
| Answer» B. \[4\hat{i}+4\hat{j}+6\hat{k}\] | |
| 694. |
It is found that \[|A+B|\,=\,|A|\]. This necessarily implies. |
| A. | \[B=0\] |
| B. | \[\vec{A},\vec{B}\] antiparallel |
| C. | \[\vec{A},\vec{B}\] are perpendicular |
| D. | \[\vec{A}.\vec{B}\le 0\] |
| Answer» C. \[\vec{A},\vec{B}\] are perpendicular | |
| 695. |
The idea of the quantum nature of light has emerged in an attempt to explain [CPMT 1990] |
| A. | Interference |
| B. | Diffraction |
| C. | Radiation spectrum of a black body |
| D. | Polarisation |
| Answer» D. Polarisation | |
| 696. |
A ring consisting of two parts ADB and ACB of same conductivity k carries an amount of heat H. The ADB part is now replaced with another metal keeping the temperatures \[{{T}_{1}}\] and \[{{T}_{2}}\] constant. The heat carried increases to 2H. What should be the conductivity of the new ADB part? Given \[\frac{ACB}{ADB}=3\]. |
| A. | \[\frac{7}{3}k\] |
| B. | \[2k\] |
| C. | \[\frac{5}{2}k\] |
| D. | \[3k\] |
| Answer» B. \[2k\] | |
| 697. |
A triangular prism of glass is inside water. A ray, incident normally, on one of the faces, is totally reflected from face BC. Then the minimum refractive index of glass is - |
| A. | \[\frac{\sqrt{3}}{2}\] |
| B. | \[\frac{5}{3}\] |
| C. | \[\frac{2\sqrt{2}}{5}\] |
| D. | \[\frac{4\sqrt{2}}{3}\] |
| Answer» E. | |
| 698. |
Assertion : Photoelectric effect demonstrates the wave nature of light. Reason : The number of photoelectrons is proportional to the frequency of light.[AIIMS 2004] |
| 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. | |
| 699. |
The units of angular momentum are [MP PMT 2000] |
| A. | \[kg-{{m}^{2}}/{{s}^{2}}\] |
| B. | \[Joule-s\] |
| C. | \[Joule/s\] |
| D. | \[kg-m-{{s}^{2}}\] |
| Answer» C. \[Joule/s\] | |
| 700. |
A second harmonic has to be generated in a string of length \[l\] stretched between two rigid supports. The point where the string has to be plucked and touched are [KCET 2001] |
| A. | Plucked at \[\frac{l}{4}\] and touch at \[\frac{l}{2}\] |
| B. | Plucked at \[\frac{l}{4}\] and touch at \[\frac{3l}{4}\] |
| C. | Plucked at \[\frac{l}{2}\] and touched at \[\frac{l}{4}\] |
| D. | Plucked at \[\frac{l}{2}\] and touched at \[\frac{3l}{4}\] |
| Answer» B. Plucked at \[\frac{l}{4}\] and touch at \[\frac{3l}{4}\] | |