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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.
| 7501. |
The resistance of a wire is 20 ohms. It is so stretched that the length becomes three times, then the new resistance of the wire will be [MP PET 1989] |
| A. | 6.67 ohms |
| B. | 60.0 ohms |
| C. | 120 ohms |
| D. | 180.0 ohms |
| Answer» E. | |
| 7502. |
Two wires of same material have length L and 2L and cross?sectional areas 4A and A respectively. The ratio of their specific resistance would be [MHCET 2002] |
| A. | 1 : 2 |
| B. | 8 : 1 |
| C. | 1 : 8 |
| D. | 1 : 1 |
| Answer» E. | |
| 7503. |
A copper wire has a square cross-section, 2.0 mm on a side. It carries a current of 8 A and the density of free electrons is \[8\times {{10}^{28}}\,{{m}^{-3}}\]. The drift speed of electrons is equal to [AMU (Med.) 2002] |
| A. | 0.156 × \[{{10}^{-3}}\] m.s?1 |
| B. | 0.156 × \[{{10}^{-2}}\] m.s?1 |
| C. | 3.12 × \[{{10}^{-3}}\] m.s?1 |
| D. | 3.12 × \[{{10}^{-2}}\] m.s?1 |
| Answer» B. 0.156 × \[{{10}^{-2}}\] m.s?1 | |
| 7504. |
The resistance of a conductor increases with [CBSE PMT 2002] |
| A. | Increase in length |
| B. | Increase in temperature |
| C. | Decrease in cross?sectional area |
| D. | All of these |
| Answer» E. | |
| 7505. |
A wire of radius r has resistance R. If it is stretched to a radius of \[\frac{3r}{4}\], its resistance becomes [BHU 2002] |
| A. | \[\frac{9R}{16}\] |
| B. | \[\frac{16R}{9}\] |
| C. | \[\frac{81R}{256}\] |
| D. | \[\frac{256R}{81}\] |
| Answer» E. | |
| 7506. |
The drift velocity of free electrons in a conductor is ?v? when a current ?i? is flowing in it. If both the radius and current are doubled, then drift velocity will be [BHU 2002] |
| A. | v |
| B. | \[\frac{v}{2}\] |
| C. | \[\frac{v}{4}\] |
| D. | \[\frac{v}{8}\] |
| Answer» C. \[\frac{v}{4}\] | |
| 7507. |
A current of 1 mA is flowing through a copper wire. How many electrons will pass a given point in one second \[\left[ e=\text{ }1.6\text{ }\times \text{ }{{10}^{19}}Coulomb \right]\] [RPMT 2000; MP PMT 2002] |
| A. | 6.25 × \[{{10}^{19}}\] |
| B. | 6.25 × \[{{10}^{15}}\] |
| C. | 6.25 × \[{{10}^{31}}\] |
| D. | 6.25 × \[{{10}^{8}}\] |
| Answer» C. 6.25 × \[{{10}^{31}}\] | |
| 7508. |
Masses of 3 wires of same metal are in the ratio 1 : 2 : 3 and their lengths are in the ratio 3 : 2 : 1. The electrical resistances are in ratio [CPMT 2002] |
| A. | 1 : 4 : 9 |
| B. | 9 : 4 : 1 |
| C. | 1 : 2 : 3 |
| D. | 27 : 6 : 1 |
| Answer» E. | |
| 7509. |
Which of the following is vector quantity [AFMC 2002] |
| A. | Current density |
| B. | Current |
| C. | Wattless current |
| D. | Power |
| Answer» B. Current | |
| 7510. |
By increasing the temperature, the specific resistance of a conductor and a semiconductor [AIEEE 2002] |
| A. | Increases for both |
| B. | Decreases for both |
| C. | Increases, decreases |
| D. | Decreases, increases |
| Answer» D. Decreases, increases | |
| 7511. |
In the figure a carbon resistor has bands of different colours on its body as mentioned in the figure. The value of the resistance is [Kerala PET 2002] |
| A. | 2.2 k W |
| B. | 3.3 k W |
| C. | 5.6 k W |
| D. | 9.1 k W |
| Answer» E. | |
| 7512. |
When the length and area of cross-section both are doubled, then its resistance [MP PET 1989] |
| A. | Will become half |
| B. | Will be doubled |
| C. | Will remain the same |
| D. | Will become four times |
| Answer» D. Will become four times | |
| 7513. |
Current of 4.8 amperes is flowing through a conductor. The number of electrons per second will be [CPMT 1986] |
| A. | \[3\times {{10}^{19}}\] |
| B. | \[7.68\times {{10}^{21}}\] |
| C. | \[7.68\times {{10}^{20}}\] |
| D. | \[3\times {{10}^{20}}\] |
| Answer» B. \[7.68\times {{10}^{21}}\] | |
| 7514. |
When two bodies collide elastically, then [CPMT 1974; MP PMT 2001; RPET 2000; Kerala PET 2005] |
| A. | Kinetic energy of the system alone is conserved |
| B. | Only momentum is conserved |
| C. | Both energy and momentum are conserved |
| D. | Neither energy nor momentum is conserved |
| Answer» D. Neither energy nor momentum is conserved | |
| 7515. |
A lead ball strikes a wall and falls down, a tennis ball having the same mass and velocity strikes the wall and bounces back. Check the correct statement |
| A. | The momentum of the lead ball is greater than that of the tennis ball |
| B. | The lead ball suffers a greater change in momentum compared with the tennis ball |
| C. | The tennis ball suffers a greater change in momentum as compared with the lead ball |
| D. | Both suffer an equal change in momentum |
| Answer» D. Both suffer an equal change in momentum | |
| 7516. |
A cannon ball is fired with a velocity 200 m/sec at an angle of 60° with the horizontal. At the highest point of its flight it explodes into 3 equal fragments, one going vertically upwards with a velocity 100 m/sec, the second one falling vertically downwards with a velocity 100 m/sec. The third fragment will be moving with a velocity [NCERT 1983; AFMC 1997] |
| A. | 100 m/s in the horizontal direction |
| B. | 300 m/s in the horizontal direction |
| C. | 300 m/s in a direction making an angle of \[60{}^\circ \]with the horizontal |
| D. | 200 m/s in a direction making an angle of \[60{}^\circ \] with the horizontal |
| Answer» C. 300 m/s in a direction making an angle of \[60{}^\circ \]with the horizontal | |
| 7517. |
A sphere collides with another sphere of identical mass. After collision, the two spheres move. The collision is inelastic. Then the angle between the directions of the two spheres is [KCET 1994] |
| A. | \[90{}^\circ \] |
| B. | \[0{}^\circ \] |
| C. | \[45{}^\circ \] |
| D. | Different from\[90{}^\circ \] |
| Answer» E. | |
| 7518. |
A mass 'm' moves with a velocity 'v' and collides inelastically with another identical mass. After collision the Ist mass moves with velocity \[\frac{v}{\sqrt{3}}\] in a direction perpendicular to the initial direction of motion. Find the speed of the 2nd mass after collision [AIEEE 2005] |
| A. | \[\frac{2}{\sqrt{3}}v\] |
| B. | \[\frac{v}{\sqrt{3}}\] |
| C. | v |
| D. | \[\sqrt{3}\,v\] |
| Answer» B. \[\frac{v}{\sqrt{3}}\] | |
| 7519. |
A ball is projected vertically down with an initial velocity from a height of 20 m onto a horizontal floor. During the impact it loses 50% of its energy and rebounds to the same height. The initial velocity of its projection is [EAMCET (Engg.) 2000] |
| A. | \[20\,m{{s}^{-1}}\] |
| B. | \[15\,m{{s}^{-1}}\] |
| C. | \[10\,m{{s}^{-1}}\] |
| D. | \[5\,m{{s}^{-1}}\] |
| Answer» B. \[15\,m{{s}^{-1}}\] | |
| 7520. |
An inelastic ball is dropped from a height of 100 m. Due to earth, 20% of its energy is lost. To what height the ball will rise [RPMT 1996] |
| A. | 80 m |
| B. | 40 m |
| C. | 60 m |
| D. | 20 m |
| Answer» B. 40 m | |
| 7521. |
The quantities remaining constant in a collision are [MP PET 1997] |
| A. | Momentum, kinetic energy and temperature |
| B. | Momentum and kinetic energy but not temperature |
| C. | Momentum and temperature but not kinetic energy |
| D. | Momentum but neither kinetic energy nor temperature |
| Answer» E. | |
| 7522. |
A body of mass m moving with velocity v makes a head-on collision with another body of mass 2 m which is initially at rest. The loss of kinetic energy of the colliding body (mass m) is [MP PMT 1996] |
| A. | \[\frac{1}{2}\] of its initial kinetic energy |
| B. | \[\frac{1}{9}\] of its initial kinetic energy |
| C. | \[\frac{8}{9}\] of its initial kinetic energy |
| D. | \[\frac{1}{4}\]of its initial kinetic energy |
| Answer» D. \[\frac{1}{4}\]of its initial kinetic energy | |
| 7523. |
Which of the following statements is true [NCERT 1984] |
| A. | In elastic collisions, the momentum is conserved but not in inelastic collisions |
| B. | Both kinetic energy and momentum are conserved in elastic as well as inelastic collisions |
| C. | Total kinetic energy is not conserved but momentum is conserved in inelastic collisions |
| D. | Total kinetic energy is conserved in elastic collisions but momentum is not conserved in elastic collisions |
| Answer» D. Total kinetic energy is conserved in elastic collisions but momentum is not conserved in elastic collisions | |
| 7524. |
Two perfectly elastic particles P and Q of equal mass travelling along the line joining them with velocities 15 m/sec and 10 m/sec. After collision, their velocities respectively (in m/sec) will be [CPMT 1988; MP PMT 1994] |
| A. | 0, 25 |
| B. | 5, 20 |
| C. | 10, 15 |
| D. | 20, 5 |
| Answer» D. 20, 5 | |
| 7525. |
A ball is allowed to fall from a height of 10 m. If there is 40% loss of energy due to impact, then after one impact ball will go up to [CPMT 1985] |
| A. | 10 m |
| B. | 8 m |
| C. | 4 m |
| D. | 6 m |
| Answer» E. | |
| 7526. |
A space craft of mass 'M' and moving with velocity 'v' suddenly breaks in two pieces of same mass m. After the explosion one of the mass 'm' becomes stationary. What is the velocity of the other part of craft [DCE 2003] |
| A. | \[\frac{Mv}{M-m}\] |
| B. | \[v\] |
| C. | \[\frac{Mv}{m}\] |
| D. | \[\frac{M-m}{m}v\] |
| Answer» B. \[v\] | |
| 7527. |
Four smooth steel balls of equal mass at rest are free to move along a straight line without friction. The first ball is given a velocity of 0.4 m/s. It collides head on with the second elastically, the second one similarly with the third and so on. The velocity of the last ball is [UPSEAT 2004] |
| A. | \[0.4m/s\] |
| B. | \[0.2m/s\] |
| C. | \[0.1m/s\] |
| D. | \[0.05m/s\] |
| Answer» B. \[0.2m/s\] | |
| 7528. |
A body of mass M moves with velocity v and collides elastically with a another body of mass m (M>>m) at rest then the velocity of body of mass m is [BCECE 2004] |
| A. | v |
| B. | 2v |
| C. | v/2 |
| D. | Zero |
| Answer» C. v/2 | |
| 7529. |
A body of mass m is at rest. Another body of same mass moving with velocity V makes head on elastic collision with the first body. After collision the first body starts to move with velocity [Orissa PMT 2004] |
| A. | V |
| B. | 2V |
| C. | Remain at rest |
| D. | No predictable |
| Answer» B. 2V | |
| 7530. |
A neutron makes a head-on elastic collision with a stationary deuteron. The fractional energy loss of the neutron in the collision is [AIIMS 2003] |
| A. | 16/81 |
| B. | 8/9 |
| C. | 8/27 |
| D. | 2/3 |
| Answer» C. 8/27 | |
| 7531. |
Two particles having position vectors \[\overrightarrow{{{r}_{1}}}=(3\hat{i}+5\hat{j})\] metres and \[\overrightarrow{{{r}_{2}}}=(-5\hat{i}-3\hat{j})\] metres are moving with velocities \[{{\overrightarrow{v}}_{1}}=(4\hat{i}+3\hat{j})\,m/s\] and \[{{\overrightarrow{v}}_{2}}=(\alpha \,\hat{i}+7\hat{j})\] \[m/s.\] If they collide after 2 seconds, the value of \['\alpha '\] is [EAMCET 2003] |
| A. | 2 |
| B. | 4 |
| C. | 6 |
| D. | 8 |
| Answer» E. | |
| 7532. |
In the elastic collision of objects [RPET 2003] |
| A. | Only momentum remains constant |
| B. | Only K.E. remains constant |
| C. | Both remains constant |
| D. | None of these |
| Answer» D. None of these | |
| 7533. |
A body of mass 2kg makes an elastic collision with another body at rest and continues to move in the original direction with one fourth of its original speed. The mass of the second body which collides with the first body is [Kerala PET 2002] |
| A. | 2 kg |
| B. | 1.2 kg |
| C. | 3 kg |
| D. | 1.5 kg |
| Answer» C. 3 kg | |
| 7534. |
A body of mass \[{{M}_{1}}\] collides elastically with another mass \[{{M}_{2}}\] at rest. There is maximum transfer of energy when [Orissa JEE 2002; DCE 2001, 02] |
| A. | \[{{M}_{1}}>{{M}_{2}}\] |
| B. | \[{{M}_{1}}<{{M}_{2}}\] |
| C. | \[{{M}_{1}}={{M}_{2}}\] |
| D. | Same for all values of \[{{M}_{1}}\] and \[{{M}_{2}}\] |
| Answer» D. Same for all values of \[{{M}_{1}}\] and \[{{M}_{2}}\] | |
| 7535. |
A ball of mass m moving with velocity V, makes a head on elastic collision with a ball of the same mass moving with velocity 2V towards it. Taking direction of V as positive velocities of the two balls after collision are [MP PMT 2002] |
| A. | \[-V\] and \[2V\] |
| B. | \[2V\]and \[-V\] |
| C. | V and\[-2V\] |
| D. | \[-2V\] and \[V\] |
| Answer» E. | |
| 7536. |
A body of mass 5 kg moving with a velocity 10m/s collides with another body of the mass 20 kg at, rest and comes to rest. The velocity of the second body due to collision is [Pb. PMT 1999; KCET 2001] |
| A. | 2.5 m/s |
| B. | 5 m/s |
| C. | 7.5 m/s |
| D. | 10 m/s |
| Answer» B. 5 m/s | |
| 7537. |
A big ball of mass M, moving with velocity u strikes a small ball of mass m, which is at rest. Finally small ball obtains velocity u and big ball v. Then what is the value of v [RPET 2001] |
| A. | \[\frac{M-m}{M+m}u\] |
| B. | \[\frac{m}{M+m}u\] |
| C. | \[\frac{2m}{M+m}u\] |
| D. | \[\frac{M}{M+m}u\] |
| Answer» B. \[\frac{m}{M+m}u\] | |
| 7538. |
A body at rest breaks up into 3 parts. If 2 parts having equal masses fly off perpendicularly each after with a velocity of 12m/s, then the velocity of the third part which has 3 times mass of each part is [UPSEAT 2001] |
| A. | \[4\sqrt{2}\,m/s\] at an angle of \[{{45}^{o}}\] from each body |
| B. | \[24\sqrt{2}\,m/s\] at an angle of \[{{135}^{o}}\]from each body |
| C. | \[6\sqrt{2}\,m/s\] at \[{{135}^{o}}\]from each body |
| D. | \[4\sqrt{2}\,m/s\] at \[{{135}^{o}}\] from each body |
| Answer» E. | |
| 7539. |
A particle falls from a height h upon a fixed horizontal plane and rebounds. If e is the coefficient of restitution, the total distance travelled before rebounding has stopped is [EAMCET 2001] |
| A. | \[h\left( \frac{1+{{e}^{2}}}{1-{{e}^{2}}} \right)\] |
| B. | \[h\left( \frac{1-{{e}^{2}}}{1+{{e}^{2}}} \right)\] |
| C. | \[\frac{h}{2}\left( \frac{1-{{e}^{2}}}{1+{{e}^{2}}} \right)\] |
| D. | \[\frac{h}{2}\left( \frac{1+{{e}^{2}}}{1-{{e}^{2}}} \right)\] |
| Answer» B. \[h\left( \frac{1-{{e}^{2}}}{1+{{e}^{2}}} \right)\] | |
| 7540. |
Two bodies having same mass 40 kg are moving in opposite directions, one with a velocity of 10\[m/s\] and the other with \[7m/s.\] If they collide and move as one body, the velocity of the combination is [Pb. PMT 2000] |
| A. | \[10\,m/s\] |
| B. | \[7m/s\] |
| C. | \[3\,m/s\] |
| D. | \[1.5\,m/s\] |
| Answer» E. | |
| 7541. |
100 g of a iron ball having velocity 10 m/s collides with a wall at an angle \[{{30}^{o}}\] and rebounds with the same angle. If the period of contact between the ball and wall is 0.1 second, then the force experienced by the ball is [DPMT 2000] |
| A. | 100N |
| B. | 10 N |
| C. | 0.1 N |
| D. | 1.0 N |
| Answer» C. 0.1 N | |
| 7542. |
A body of mass \[{{m}_{1}}\] moving with a velocity 3 ms?1 collides with another body at rest of mass \[{{m}_{2}}.\]After collision the velocities of the two bodies are 2 ms?1 and 5ms?1 respectively along the direction of motion of \[{{m}_{1}}\] The ratio \[{{m}_{1}}/{{m}_{2}}\] is [EAMCET (Engg.) 2000] |
| A. | \[\frac{5}{12}\] |
| B. | \[5\] |
| C. | \[\frac{1}{5}\] |
| D. | \[\frac{12}{5}\] |
| Answer» C. \[\frac{1}{5}\] | |
| 7543. |
A sphere of mass m moving with a constant velocity u hits another stationary sphere of the same mass. If e is the coefficient of restitution, then the ratio of the velocity of two spheres after collision will be [RPMT 1996; BHU 1997] |
| A. | \[\frac{1-e}{1+e}\] |
| B. | \[\frac{1+e}{1-e}\] |
| C. | \[\frac{e+1}{e-1}\] |
| D. | \[\frac{e-1}{e+1}{{t}^{2}}\] |
| Answer» B. \[\frac{1+e}{1-e}\] | |
| 7544. |
A body falling from a height of 10m rebounds from hard floor. If it loses 20% energy in the impact, then coefficient of restitution is [AIIMS 2000] |
| A. | 0.89 |
| B. | 0.56 |
| C. | 0.23 |
| D. | 0.18 |
| Answer» B. 0.56 | |
| 7545. |
A bullet of mass 50 gram is fired from a 5 kg gun with a velocity of 1km/s. the speed of recoil of the gun is [JIPMER 1999] |
| A. | \[5\,m/s\] |
| B. | \[1\,m/s\] |
| C. | \[0.5\,m/s\] |
| D. | \[10\,m/s\] |
| Answer» E. | |
| 7546. |
A space craft of mass M is moving with velocity V and suddenly explodes into two pieces. A part of it of mass m becomes at rest, then the velocity of other part will be [RPMT 1999] |
| A. | \[\frac{MV}{M-m}\] |
| B. | \[\frac{MV}{M+m}\] |
| C. | \[\frac{mV}{M-m}\] |
| D. | \[\frac{(M+m)V}{m}\] |
| Answer» B. \[\frac{MV}{M+m}\] | |
| 7547. |
A ball hits a vertical wall horizontally at 10m/s bounces back at 10 m/s [JIPMER 1999] |
| A. | There is no acceleration because \[10\,\frac{m}{s}-\,10\frac{m}{s}=0\] |
| B. | There may be an acceleration because its initial direction is horizontal |
| C. | There is an acceleration because there is a momentum change |
| D. | Even though there is no change in momentum there is a change in direction. Hence it has an acceleration |
| Answer» D. Even though there is no change in momentum there is a change in direction. Hence it has an acceleration | |
| 7548. |
A body of mass 50 kg is projected vertically upwards with velocity of 100 m/sec. 5 seconds after this body breaks into 20 kg and 30 kg. If 20 kg piece travels upwards with 150 m/sec, then the velocity of other block will be [RPMT 1999] |
| A. | 15 m/sec downwards |
| B. | 15 m/sec upwards |
| C. | 51 m/sec downwards |
| D. | 51 m/sec upwards |
| Answer» B. 15 m/sec upwards | |
| 7549. |
A steel ball of radius 2 cm is at rest on a frictionless surface. Another ball of radius 4cm moving at a velocity of 81 cm/sec collides elastically with first ball. After collision the smaller ball moves with speed of [RPMT 1999] |
| A. | 81 cm/sec |
| B. | 63 cm/sec |
| C. | 144 cm/sec |
| D. | None of these |
| Answer» D. None of these | |
| 7550. |
A ball of mass m falls vertically to the ground from a height h1 and rebound to a height \[{{h}_{2}}\]. The change in momentum of the ball on striking the ground is [AMU (Engg.) 1999] |
| A. | \[mg({{h}_{1}}-{{h}_{2}})\] |
| B. | \[m(\sqrt{2g{{h}_{1}}}+\sqrt{2g{{h}_{2}}})\] |
| C. | \[m\sqrt{2g({{h}_{1}}+{{h}_{2}})}\] |
| D. | \[m\sqrt{2g}({{h}_{1}}+{{h}_{2}})\] |
| Answer» C. \[m\sqrt{2g({{h}_{1}}+{{h}_{2}})}\] | |