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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.
| 1851. |
A beam of electrons is moving with constant velocity in a region having simultaneous perpendicular electric and magnetic fields of strength \[20\,V{{m}^{-1}}\] and 0.5 T respectively at right angles to the direction of motion of the electrons. Then the velocity of electrons must be |
| A. | \[8\,m/s\] |
| B. | \[20\,m/s\] |
| C. | \[40\,m/s\] |
| D. | \[\frac{1}{40}\,m/s\] |
| Answer» D. \[\frac{1}{40}\,m/s\] | |
| 1852. |
A current of I ampere flows in a wire forming a circular arc of radius r metres subtending an angle \[\theta \] at the centre as shown. The magnetic field at the centre O in tesla is |
| A. | \[\frac{{{\mu }_{0}}I\theta }{4\pi r}\] |
| B. | \[\frac{{{\mu }_{0}}I\theta }{2\pi r}\] |
| C. | \[\frac{{{\mu }_{0}}I\theta }{2r}\] |
| D. | \[\frac{{{\mu }_{0}}I\theta }{4r}\] |
| Answer» B. \[\frac{{{\mu }_{0}}I\theta }{2\pi r}\] | |
| 1853. |
A helium nucleus makes a full rotation in a circle of radius 0.8 meter in 2 sec. The value of the magnetic field induction B in tesla at the centre of circle will be |
| A. | \[2\times {{10}^{-19}}{{\mu }_{0}}\] |
| B. | \[{{10}^{-19}}/{{\mu }_{0}}\] |
| C. | \[{{10}^{-19}}{{\mu }_{0}}\] |
| D. | \[2\times {{10}^{-20}}/{{\mu }_{0}}\] |
| Answer» D. \[2\times {{10}^{-20}}/{{\mu }_{0}}\] | |
| 1854. |
A particle of mass m and charge q enters a region of magnetic field (as shown) with speed v. There is a region in which the magnetic field is absent, as shown. The particle after entering the region collides elastically with a rigid wall. Time after which the velocity of particle becomes antiparallel to its initial velocity is |
| A. | \[\frac{m}{2qB}(\pi +4)\] |
| B. | \[\frac{m}{qB}(\pi +2)\] |
| C. | \[\frac{m}{4qB}(\pi +2)\] |
| D. | \[\frac{m}{4qB}(2\pi +3)\] |
| Answer» B. \[\frac{m}{qB}(\pi +2)\] | |
| 1855. |
The figure shows a thin metalic rod whose one end is pivoted at point 0. The rod rotates about the end O in a plane perpendicular to the uniform magnetic field with angular frequency \[\omega \] in clockwise direction. Which of the following is correct? |
| A. | The free electrons of the rod move towards the outer end |
| B. | The free electrons of the rod move towards the pivoted end. |
| C. | The free electrons of the rod move towards the mid-point of the rod. |
| D. | The free electrons of the rod do not move towards any end of the rod as rotation of rod has no effect on motion of free electrons. |
| Answer» C. The free electrons of the rod move towards the mid-point of the rod. | |
| 1856. |
A charged particle of specific charge (charge/ mass) \[\alpha \] is released from origin at time t = 0 with velocity \[\overset{\to }{\mathop{v}}\,={{v}_{0}}(\hat{i}+\hat{j})\] in uniform magnetic field \[\overset{\to }{\mathop{B}}\,={{B}_{0}}\hat{i}\]. Coordinates of the particle at time \[t=\pi /({{B}_{0}}\alpha )\] |
| A. | \[\left( \frac{{{v}_{0}}}{2{{B}_{0}}\alpha },\frac{\sqrt{2}{{v}_{0}}}{\alpha {{B}_{0}}},\frac{-{{v}_{0}}}{{{B}_{0}}\alpha } \right)\] |
| B. | \[\left( \frac{-{{v}_{0}}}{2{{B}_{0}}\alpha },0,0 \right)\] |
| C. | \[\left( 0,\frac{2{{v}_{0}}}{{{B}_{0}}\alpha },\frac{{{v}_{0}}\pi }{2{{B}_{0}}\alpha } \right)\] |
| D. | \[\left( \frac{{{v}_{0}}\pi }{{{B}_{0}}\pi },0\frac{-2{{v}_{0}}}{{{B}_{0}}\alpha } \right)\] |
| Answer» E. | |
| 1857. |
A cyclotron is operated at an oscillator frequency of 24 MHz and has a dee radius\[R=60cm\]. What is magnitude of the magnetic field B (in Tesla) to accelerate deuterons\[(mass=3.34\times {{10}^{-27}})kg\]? |
| A. | 9.5 |
| B. | 7.2 |
| C. | 5.0 |
| D. | 3.2 |
| Answer» E. | |
| 1858. |
A positive charge 'q' of mass 'm' is moving along the +x axis. We wish to apply a uniform magnetic field B for time \[\Delta \,t\] so that the charge reverses its direction crossing the y axis at a distance d. Then: |
| A. | \[B=\frac{mv}{qd}\] and \[\Delta t=\frac{\pi d}{v}\] |
| B. | \[B=\frac{mv}{2qd}\] and \[\Delta t=\frac{\pi d}{2v}\] |
| C. | \[B=\frac{2mv}{qd}\] and \[\Delta t=\frac{\pi d}{2v}\] |
| D. | \[B=\frac{2mv}{qd}\] and \[\Delta t=\frac{\pi d}{v}\] |
| Answer» D. \[B=\frac{2mv}{qd}\] and \[\Delta t=\frac{\pi d}{v}\] | |
| 1859. |
A charged sphere of mass m and charge - q starts sliding along the surface of a smooth hemispherical bowl, at position P. The region has a transverse uniform magnetic field B. Normal force by the surface of bowl on the sphere at position Q is |
| A. | \[mg\,\sin \theta +qB\sqrt{2g\,R\,\sin \,\theta }\] |
| B. | \[3\,mg\,\sin \theta +qB\sqrt{2g\,R\,\sin \,\theta }\] |
| C. | \[mg\,\sin \theta -qB\sqrt{2g\,R\,\sin \,\theta }\] |
| D. | \[3\,mg\,\sin \theta -qB\sqrt{2g\,R\,\sin \,\theta }\] |
| Answer» C. \[mg\,\sin \theta -qB\sqrt{2g\,R\,\sin \,\theta }\] | |
| 1860. |
An electric charge \[+q\] moves with velocity \[10m{{s}^{-1}}\]in an electromagnetic field given by \[\overset{\to }{\mathop{E}}\,=3\hat{i}+\hat{j}+2\hat{k}\] and \[\overset{\to }{\mathop{B}}\,=\hat{i}+\hat{j}-3\hat{k}\] The y- component of the force experienced by \[+q\] is: |
| A. | \[11\,\,q\] |
| B. | \[5\,q\] |
| C. | \[3\,q\] |
| D. | \[2\,q\] |
| Answer» B. \[5\,q\] | |
| 1861. |
Two identical particles having the same mass m and charges +q and -q separated by a distance d enter a uniform magnetic field B directed perpendicular to paper inwards with in speeds \[{{v}_{1}}\] and \[{{v}_{2}}\] as shown in Fig. The particles will not collide if |
| A. | \[d>\frac{m}{Bq}({{v}_{1}}+{{v}_{2}})\] |
| B. | \[d<\frac{m}{Bq}({{v}_{1}}+{{v}_{2}})\] |
| C. | \[d>\frac{2m}{Bq}({{v}_{1}}+{{v}_{2}})\] |
| D. | \[{{v}_{1}}={{v}_{2}}\] |
| Answer» D. \[{{v}_{1}}={{v}_{2}}\] | |
| 1862. |
A particle of charge q and mass m starts moving from the origin under the action of an electric field \[\overset{\to }{\mathop{E}}\,={{E}_{0}}\hat{i}\] and \[\overset{\to }{\mathop{B}}\,={{B}_{0}}\hat{i}\] with velocity \[\overset{\to }{\mathop{v}}\,={{v}_{0}}\hat{j}\] .The speed of the particle will become\[2{{v}_{0}}\] after time |
| A. | \[t=\frac{2m{{v}_{0}}}{qE}\] |
| B. | \[t=\frac{2Bq}{m{{v}_{0}}}\] |
| C. | \[t=\frac{\sqrt{3}Bq}{m{{v}_{0}}}\] |
| D. | \[t=\frac{\sqrt{3}m{{v}_{0}}}{qE}\] |
| Answer» E. | |
| 1863. |
A deuteron of kinetic energy 50 ke V is describing a circular orbit of radius 0.5 metre in a plane perpendicular to the magnetic field B. The kinetic energy of the proton that describes a circular orbit of radius 0.5 metre in the same plane with the same B is |
| A. | \[25\,ke\,V\] |
| B. | \[50\,ke\,V\] |
| C. | \[200\,ke\,V\] |
| D. | \[100\,ke\,V\] |
| Answer» E. | |
| 1864. |
An alternating electric field, of frequency v, is applied across the dees (radius=R) of a cyclotron that is being used to accelerate protons (mass=m). The operating magnetic field used in the cyclotron and the kinetic energy (K) of the proton beam, produced by it, are given by: |
| A. | \[B=\frac{mv}{e}\]and \[K=2m{{\pi }^{2}}{{v}^{2}}{{R}^{2}}\] |
| B. | \[B=\frac{2\pi mv}{e}\] and \[K={{m}^{2}}\pi v{{R}^{2}}\] |
| C. | \[B=\frac{2\pi mv}{e}\] and \[K=2m{{\pi }^{2}}{{v}^{2}}{{R}^{2}}\] |
| D. | \[B=\frac{mv}{e}\] and \[K={{m}^{2}}\pi v{{R}^{2}}\] |
| Answer» D. \[B=\frac{mv}{e}\] and \[K={{m}^{2}}\pi v{{R}^{2}}\] | |
| 1865. |
A 10 eV electron is circulating in a plane at right angles to a uniform field at magnetic induction \[{{10}^{-4}}Wb/{{m}^{2}}\] (=1.0 gauss). The orbital radius of the electron is |
| A. | 12cm |
| B. | 16cm |
| C. | 11cm |
| D. | 18cm |
| Answer» D. 18cm | |
| 1866. |
An electron, charge?e, mass m, enters a uniform magnetic field \[\overset{\to }{\mathop{B}}\,=B\overset{\to }{\mathop{i}}\,\] with an initial velocity \[\overset{\to }{\mathop{v}}\,={{v}_{x}}\overset{\to }{\mathop{i}}\,+{{v}_{y}}\overset{\to }{\mathop{j}}\,\]. What is the velocity of the electron after a time interval of t second? |
| A. | \[{{v}_{x}}\hat{i}+{{v}_{y}}\hat{j}+\frac{e}{m}{{v}_{y}}B\,t\,\hat{k}\] |
| B. | \[{{v}_{x}}\hat{i}+{{v}_{y}}\hat{j}-\frac{e}{m}{{v}_{y}}B\,t\,\hat{k}\] |
| C. | \[{{v}_{x}}\hat{i}+\left( {{v}_{y}}+\frac{e}{m}{{v}_{y}}B\,t\, \right)\hat{j}\] |
| D. | \[{{v}_{x}}\hat{i}+\left( {{v}_{y}}+\frac{e}{m}{{v}_{y}}B\,t\, \right)\hat{i}+{{v}_{y}}\hat{j}\] |
| Answer» B. \[{{v}_{x}}\hat{i}+{{v}_{y}}\hat{j}-\frac{e}{m}{{v}_{y}}B\,t\,\hat{k}\] | |
| 1867. |
A uniform magnetic field of magnitude IT exists in region y>0 is along k direction as shown. A particle of charge 1 C is projected from point \[(-\sqrt{3},-1)\] towards origin with speed 1 m/sec. If mass of particle is 1 kg, then co-ordinates of centre of circle in which particle moves are- |
| A. | \[(1,\,\sqrt{3})\] |
| B. | \[(1,\,-\sqrt{3})\] |
| C. | \[\left( \frac{1}{2},-\frac{\sqrt{3}}{2} \right)\] |
| D. | \[\left( \frac{\sqrt{3}}{2},-\frac{1}{2} \right)\] |
| Answer» D. \[\left( \frac{\sqrt{3}}{2},-\frac{1}{2} \right)\] | |
| 1868. |
Two particles X and Y having equal charges, after being accelerated through the same potential difference, enter a region of uniform magnetic field and describe circular paths of radii \[{{R}_{1}}\]and \[{{R}_{2}}\] respectively. The ratio of the mass of X to that of Y is |
| A. | \[{{({{R}_{1}}/{{R}_{2}})}^{1/2}}\] |
| B. | \[{{R}_{2}}/{{R}_{1}}\] |
| C. | \[{{({{R}_{1}}/{{R}_{2}})}^{2}}\] |
| D. | \[{{R}_{1}}/{{R}_{2}}\] |
| Answer» D. \[{{R}_{1}}/{{R}_{2}}\] | |
| 1869. |
For a positively charged particle moving in a x-y plane initially along the x-axis, there is a sudden change in its path due to the presence of electric and/or magnetic fields beyond P. The curved path is shown in the x-y plane and is found to be non- circular. Which one of the following combinations is possible? |
| A. | \[\overset{\to }{\mathop{E}}\,=0;\overset{\to }{\mathop{B}}\,=b\hat{i}+c\hat{k}\] |
| B. | \[\overset{\to }{\mathop{E}}\,=a\hat{i};\overset{\to }{\mathop{B}}\,=c\hat{k}+a\hat{i}\] |
| C. | \[\overset{\to }{\mathop{E}}\,=0;\overset{\to }{\mathop{B}}\,=c\hat{j}+b\hat{k}\] |
| D. | \[\overset{\to }{\mathop{E}}\,=a\hat{i};\overset{\to }{\mathop{B}}\,=c\hat{k}+b\hat{j}\] |
| Answer» C. \[\overset{\to }{\mathop{E}}\,=0;\overset{\to }{\mathop{B}}\,=c\hat{j}+b\hat{k}\] | |
| 1870. |
A particle of mass m and charge q moves with a constant velocity v along the positive x-direction. It enters a region containing a uniform magnetic field B directed along the negative z-direction, extending from \[x=a\] to \[~x=b\]. The minimum value of v required so that the particle can just enter the region x > b is |
| A. | \[\frac{qbB}{m}\] |
| B. | \[\frac{q(b-a)B}{m}\] |
| C. | \[\frac{qaB}{m}\] |
| D. | \[\frac{q(b+a)B}{2m}\] |
| Answer» C. \[\frac{qaB}{m}\] | |
| 1871. |
There exist uniform magnetic and electric fields of magnitudes 1T and \[1\,V\,{{m}^{-1}}\], respectively, along positive y-axis. A charged particle of mass 1 kg and charge 1 C is having velocity \[1\,\,m\,{{s}^{-1}}\] along x-axis and is at origin at t=0. Then, the coordinates of the particles at time \[\pi s\] will be |
| A. | \[(0,\,\,1,\,\,2)m\] |
| B. | \[(0,\,-{{\pi }^{2}},\,-2)m\] |
| C. | \[(2,\,{{\pi }^{2}}/2,\,2)m\] |
| D. | \[(0,\,\,{{\pi }^{2}}/2,\,\,2)m\] |
| Answer» E. | |
| 1872. |
Consider a hypothetic spherical body. The body is cut into two parts about the diameter. One of hemispherical portion has mass distribution m whie the other portion has identical charge distribution q. The body is rotated about the axis with constant speed o. Then, the ratio of magnetic moment to angular momentum is |
| A. | \[\frac{q}{2m}\] |
| B. | \[>\frac{q}{2m}\] |
| C. | \[<\frac{q}{2m}\] |
| D. | cannot be calculated |
| Answer» B. \[>\frac{q}{2m}\] | |
| 1873. |
A particle is projected in a plane perpendicular to a uniform magnetic field. The area bounded by the path described by the particle is proportional to |
| A. | the velocity |
| B. | the momentum |
| C. | the kinetic energy |
| D. | None of these |
| Answer» D. None of these | |
| 1874. |
A particle of specific charge \[\frac{q}{m}=\pi \,\,Ck{{g}^{-1}}\]is projected from the origin towards positive x-axis with a velocity of \[10m{{s}^{-1}}\] in a uniform magnetic field \[\overset{\to }{\mathop{B}}\,=-2\hat{k}\,T\] . The velocity \[\overrightarrow{v}\]of particle after time = 1/12 s will be \[(in\,m{{s}^{-1}})\] |
| A. | \[5[\hat{i}+\sqrt{3}\hat{j}]\] |
| B. | \[5[\sqrt{3}\hat{i}+\hat{j}]\] |
| C. | \[5[\sqrt{3\hat{i}}-\hat{j}]\] |
| D. | \[5[\hat{i}-\hat{j}]\] |
| Answer» C. \[5[\sqrt{3\hat{i}}-\hat{j}]\] | |
| 1875. |
Three particles, an electron (e), a proton (p) and a helium atom (He) are moving in circular paths with constant speeds in the x - y plane in a region where a uniform magnetic field B exists along z - axis. The times taken bye, p and He inside the field to complete one revolution are \[{{t}_{e}}\], \[{{t}_{p}}\] and \[{{t}_{He}}\] respectively. Then, |
| A. | \[{{t}_{He}}>{{t}_{p}}={{t}_{e}}\] |
| B. | \[{{t}_{He}}>{{t}_{p}}>{{t}_{e}}\] |
| C. | \[{{t}_{He}}={{t}_{p}}={{t}_{e}}\] |
| D. | None of these |
| Answer» C. \[{{t}_{He}}={{t}_{p}}={{t}_{e}}\] | |
| 1876. |
An ionized gas contains both positive and negative ions. If it is subjected simultaneously to an electric field along the \[+x\]-direction and a magnetic field along the \[+z\]-direction, then |
| A. | positive ions deflect towards \[+y\]-direction and negative ions towards -y direction |
| B. | all ions deflect towards \[+y\]-direction |
| C. | all ions deflect towards \[~-y\]-direction |
| D. | positive ions deflect towards \[~-y\]-direction and negative ions towards \[~+y\]-direction. |
| Answer» D. positive ions deflect towards \[~-y\]-direction and negative ions towards \[~+y\]-direction. | |
| 1877. |
A moving coil galvanometer has a resistance of\[900\Omega \]. In order to send only 10% of the main current through this galvanometer, the resistance of the required shunt is |
| A. | \[0.9\Omega \] |
| B. | \[100\Omega \] |
| C. | \[405\Omega \] |
| D. | \[90\Omega \] |
| Answer» C. \[405\Omega \] | |
| 1878. |
A ball is dropped from the top of a building. The ball takes 0.5 s to fall past the 3 m length of a window some distance from the top of the building. If the velocities of the ball at the top and at the bottom of the window are \[{{v}_{T}}\] and \[{{v}_{B}}\] respectively, then \[(take\text{ }g=10\text{ }m/{{s}^{2}})\] |
| A. | \[{{\text{v}}_{\text{T}}}\text{+}{{\text{v}}_{\text{B}}}\text{=12m}{{\text{s}}^{-1}}\] |
| B. | \[{{\text{v}}_{\text{T}}}-{{\text{v}}_{\text{B}}}=4.9\text{m}{{\text{s}}^{-1}}\] |
| C. | \[{{\text{v}}_{\text{B}}}{{\text{v}}_{\text{T}}}\text{=1m}{{\text{s}}^{-1}}\] |
| D. | \[{{\text{v}}_{\text{B}}}\text{/}{{\text{v}}_{\text{T}}}\text{=1m}{{\text{s}}^{-1}}\] |
| Answer» C. \[{{\text{v}}_{\text{B}}}{{\text{v}}_{\text{T}}}\text{=1m}{{\text{s}}^{-1}}\] | |
| 1879. |
A particle when thrown, moves such that it passes from same height at 2 and 10 seconds, then this height h is: |
| A. | 5g |
| B. | g |
| C. | 8g |
| D. | 10g |
| Answer» E. | |
| 1880. |
A body A is thrown vertically upward with the initial velocity \[{{v}_{1}}\]. Another body B is dropped from a height h. Find how the distance x between the bodies depends on the time t if the bodies begin to move simultaneously. |
| A. | \[x=h-{{v}_{1}}t\] |
| B. | \[x=\left( h-{{v}_{1}} \right)t\] |
| C. | \[x=h-\frac{{{v}_{1}}}{t}\] |
| D. | \[x=\frac{h}{t}-{{v}_{1}}\] |
| Answer» B. \[x=\left( h-{{v}_{1}} \right)t\] | |
| 1881. |
From a pole of height 10 m, a stone is thrown vertically upwards with a speed 5 m/s. The time taken by the stone, to hit the ground, is n times that taken by it to reach the highest point of its path. The value of n is \[[take\text{ }g=10\text{ }m/{{s}^{2}}]\] |
| A. | 2 |
| B. | 3 |
| C. | 4 |
| D. | 5 |
| Answer» D. 5 | |
| 1882. |
A body is thrown upwards. If air resistance causing deceleration of \[5\text{ }m/{{s}^{2}}\], then ratio of time of ascent to time of descent is \[[take\text{ }g=10\text{ }m/{{s}^{2}}]\] |
| A. | \[\sqrt{\frac{1}{2}}\] |
| B. | \[\sqrt{\frac{1}{2.5}}\] |
| C. | \[\sqrt{\frac{1}{3}}\] |
| D. | \[\sqrt{\frac{1}{5}}\] |
| Answer» D. \[\sqrt{\frac{1}{5}}\] | |
| 1883. |
A body thrown vertically so as to reach its maximum height in t second. The total time from the time of projection to reach a point at half of its maximum height while returning (in sec) is |
| A. | \[\sqrt{\text{2}}\text{t}\] |
| B. | \[\left( \text{1+}\frac{\text{1}}{\sqrt{\text{2}}} \right)\text{t}\] |
| C. | \[\frac{\text{3t}}{\text{2}}\] |
| D. | \[\frac{\text{t}}{\sqrt{\text{2}}}\] |
| Answer» C. \[\frac{\text{3t}}{\text{2}}\] | |
| 1884. |
A ball is dropped from the top of a tower of height 100 m and at the same time another ball is projected vertically upwards from ground with a velocity \[25\text{ }m{{s}^{-1}}\]. Then the distance from the top of the tower, at which the two balls meet is |
| A. | 68.4 m |
| B. | 48.4 m |
| C. | 18.4 m |
| D. | 78.4 m |
| Answer» E. | |
| 1885. |
A ball is thrown vertically upwards. It was observed, at a height h twice with a time interval \[\Delta \,t\]. The initial velocity of the ball is |
| A. | \[\sqrt{8gh+{{g}^{2}}{{\left( \Delta \,t \right)}^{2}}}\] |
| B. | \[\sqrt{8gh+{{\left( \frac{g\Delta \,t}{2} \right)}^{2}}}\] |
| C. | \[\frac{1}{2}\sqrt{8gh+{{g}^{2}}{{\left( \Delta \,t \right)}^{2}}}\] |
| D. | \[\sqrt{8gh+4{{g}^{2}}{{\left( \Delta \,t \right)}^{2}}}\] |
| Answer» D. \[\sqrt{8gh+4{{g}^{2}}{{\left( \Delta \,t \right)}^{2}}}\] | |
| 1886. |
If distance covered by a particle is zero, what can you say about its displacement? |
| A. | It may or may not be zero |
| B. | It cannot be zero |
| C. | It is negative |
| D. | It must be zero |
| Answer» E. | |
| 1887. |
A stone is dropped into a well in which the level of water is h below the top of the well. If v is velocity of sound, the time T after which the splash is heard is given by |
| A. | \[T=2h/v\] |
| B. | \[\text{T=}\sqrt{\left( \frac{\text{2h}}{\text{g}} \right)\text{+}\frac{\text{h}}{\text{v}}}\] |
| C. | \[\text{T=}\sqrt{\left( \frac{\text{2h}}{\text{g}} \right)}\text{+}\frac{\text{h}}{\text{g}}\] |
| D. | \[\text{T=}\sqrt{\left( \frac{\text{h}}{\text{2g}} \right)}\text{+}\frac{\text{2h}}{\text{v}}\] |
| Answer» C. \[\text{T=}\sqrt{\left( \frac{\text{2h}}{\text{g}} \right)}\text{+}\frac{\text{h}}{\text{g}}\] | |
| 1888. |
A ball is released from the top of tower of height h meter. It takes T second to reach the ground. What is the position in (m) from the ground of the ball in T/3 second? |
| A. | \[\frac{h}{9}\] |
| B. | \[\frac{7h}{9}\] |
| C. | \[\frac{8h}{9}\] |
| D. | \[\frac{17h}{18}\] |
| Answer» D. \[\frac{17h}{18}\] | |
| 1889. |
From a building two balls A and B are thrown such that A is thrown upwards and B downwards (both vertically). If \[{{T}_{A}}\] and \[{{T}_{B}}\] are their respective time of flights then |
| A. | \[{{T}_{A}}>{{T}_{B}}\] |
| B. | \[{{T}_{A}}={{T}_{B}}\] |
| C. | \[{{T}_{A}}<{{T}_{B}}\] |
| D. | Their time of flights depend on their masses. |
| Answer» B. \[{{T}_{A}}={{T}_{B}}\] | |
| 1890. |
A ball is dropped from a high rise platform at t = 0 starting from rest. After 6 seconds another ball is thrown downwards from the same platform with a speed v. The two balls meet at t = 18s. What is the value of v? \[(take\text{ }g=10\text{ }m/{{s}^{2}})\] |
| A. | 75 m/s |
| B. | 55 m/s |
| C. | 40 m/s |
| D. | 60 m/s |
| Answer» B. 55 m/s | |
| 1891. |
A ball dropped from a point A falls down vertically to C, through the midpoint B. The descending time from A to B and that from A to C are in the ratio |
| A. | 1 : 1 |
| B. | 1 : 2 |
| C. | 1 : 3 |
| D. | \[1:\sqrt{2}\] |
| Answer» E. | |
| 1892. |
From a balloon moving upwards with a velocity of \[12\text{ }m{{s}^{-1}}\], a packet is released when it is at a height of 65 m from the ground. 7 lie time taken by it to reach the ground is \[(g=10\text{ }m{{s}^{-2}})\] |
| A. | 5s |
| B. | 8s |
| C. | 4s |
| D. | 7s |
| Answer» B. 8s | |
| 1893. |
A boy standing at the top of a tower of 20 m height drops a stone. Assuming \[g=10\text{ }m{{s}^{-2}}\], the velocity with which it hits the ground is |
| A. | \[10.0\,m/s\] |
| B. | \[20.0\,m/s\] |
| C. | \[40.0\,m/s\] |
| D. | \[5.0\,m/s\] |
| Answer» C. \[40.0\,m/s\] | |
| 1894. |
What will be the ratio of the distances moved by a freely falling body from rest on 4th and 5th seconds of journey? |
| A. | 4 : 5 |
| B. | 7 : 9 |
| C. | 0.684027777777778 |
| D. | 0.0423611111111111 |
| Answer» C. 0.684027777777778 | |
| 1895. |
In 1.0 s, a particle goes from point A to point B, moving in a semicircle of radius 1.0 m (see Figure). The magnitude of the average velocity is |
| A. | \[3.14\,\,m/s\] |
| B. | \[2.0\,\,m/s\] |
| C. | \[1.0\text{ }m/s\] |
| D. | Zero |
| Answer» C. \[1.0\text{ }m/s\] | |
| 1896. |
If two balls of masses \[{{m}_{1}}\] and \[{{m}_{2}}({{m}_{1}}=2{{m}_{2}})\] are dropped from the same height, then the ratio of the time taken by them to reach the ground will be |
| A. | \[{{m}_{1}}:{{m}_{2}}\] |
| B. | \[2{{m}_{2}}:{{m}_{1}}\] |
| C. | 1 : 1 |
| D. | 0.0430555555555556 |
| Answer» D. 0.0430555555555556 | |
| 1897. |
Let A, B, C, D be points on a vertical line such that AB = BC = CD. If a body is released from position A, the times of descent through AB, BC and CD are in the ratio. |
| A. | \[1:\sqrt{3}-\sqrt{2}:\sqrt{3}+\sqrt{2}\] |
| B. | \[1:\sqrt{2}-1:\sqrt{3}-\sqrt{2}\] |
| C. | \[1:\sqrt{2}-1:\sqrt{3}\] |
| D. | \[1:\sqrt{2}:\sqrt{3}-1\] |
| Answer» C. \[1:\sqrt{2}-1:\sqrt{3}\] | |
| 1898. |
A rocket is fired upward from the earth's surface such that it creates an acceleration of \[19.6\,\,m{{s}^{-2}}\]. If after 5 s, its engine is switched off, the maximum height of the rocket from earth's surface would be |
| A. | 980 m |
| B. | 735 m |
| C. | 490 m |
| D. | 245 m |
| Answer» C. 490 m | |
| 1899. |
A man throws balls with same speed vertically upwards one after the other at an interval of 2 sec. What should be the speed of throw so that more man two balls are in air at any time? |
| A. | Only with speed 19.6 m/s |
| B. | More than 19.6 m/s |
| C. | At least 9.8 m/s |
| D. | Any speed less than 19.6 m/s. |
| Answer» C. At least 9.8 m/s | |
| 1900. |
Two balls A and B of same mass are thrown from the top of the building. A thrown upward with velocity v and B, thrown down with velocity v, hen |
| A. | velocity A is more than B at the ground |
| B. | velocity of B is more than A at the ground |
| C. | both A & B strike the ground with same velocity |
| D. | None of these |
| Answer» D. None of these | |