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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.
| 3151. |
The r.m.s. value of potential difference V shown in the figure is |
| A. | \[{{V}_{0}}\] |
| B. | \[{{V}_{0}}/\sqrt{2}\] |
| C. | \[{{V}_{0}}/2\] |
| D. | \[{{V}_{0}}/\sqrt{3}\] |
| Answer» C. \[{{V}_{0}}/2\] | |
| 3152. |
Determine the rms value of a semi-circular current wave which has a maximum value of a. |
| A. | \[(1\sqrt{2})a\] |
| B. | \[(\sqrt{3/2})a\] |
| C. | \[(\sqrt{2/3})a\] |
| D. | \[(\sqrt{1/3})a\] |
| Answer» D. \[(\sqrt{1/3})a\] | |
| 3153. |
In an L-R circuit, the value of L is \[(0.4/\pi )\]henry and the value of R is 30 ohm. If in the circuit, an alternating emfof200 volt at 50 cycles per second is connected, the impedance of the circuit and current will be: |
| A. | 11.4 ohm, 17.5 ampere |
| B. | 30.7 ohm, 6.5 ampere |
| C. | 40.4 ohm, 5 ampere |
| D. | 50 ohm, 4 ampere. |
| Answer» E. | |
| 3154. |
Of the following about capacitive reactance which is correct? |
| A. | The reactance of the capacitor is directly proportional to its ability to store charge |
| B. | Capacitive reactance is inversely proportional to the frequency of the current |
| C. | Capacitive reactance is measured in farad |
| D. | The reactance of a capacitor in an A.C. circuit is similar to the resistance of a capacitor in a D.C. circuit |
| Answer» C. Capacitive reactance is measured in farad | |
| 3155. |
The equation of AC voltage is\[E=220\,\sin \,(\omega t+\pi /6)\] and the A.C. current\[I=10\,\sin \,(\omega t+\pi /6)\]. The average power dissipated is |
| A. | 150 W |
| B. | 550 W |
| C. | 250 W |
| D. | 50 W |
| Answer» C. 250 W | |
| 3156. |
The voltage of an ac supply varies with time (t) I as\[V=120\,\sin \,100\pi \,t\,\cos \,100\pi t\]. The maximum voltage and frequency respectively are |
| A. | 120 volts, 100 Hz |
| B. | \[\frac{120}{\sqrt{2}}volts,\,\,100Hz\] |
| C. | 60 volts, 200 Hz |
| D. | 60 volts, 100 Hz |
| Answer» E. | |
| 3157. |
Resonance frequency of a circuit is f. If the capacitance is made 4 times the initial value, the resonance frequency will become : |
| A. | \[f/2\] |
| B. | 2f |
| C. | f |
| D. | f/4 |
| Answer» B. 2f | |
| 3158. |
A coil of inductance 8.4 mH and resistance \[6\,\Omega \] is connected to a 12 V battery. The current in the coil is 1.0 A at approximately the time |
| A. | 500s |
| B. | 25s |
| C. | 35ms |
| D. | 1ms |
| Answer» E. | |
| 3159. |
The transformer voltage induced in the secondary coil of a transformer is mainly due to |
| A. | a varying electric field |
| B. | a varying magnetic field |
| C. | the vibrations of the primary coil |
| D. | the iron core of the transformer |
| Answer» C. the vibrations of the primary coil | |
| 3160. |
Figure shows one cycle of an alternating current with the segments AB, BC, CD, DE being symmetrical and parabolic. The root mean square value of this current over one cycle is x mA, find x. |
| A. | 1mA |
| B. | 2mA |
| C. | 3mA |
| D. | 4mA |
| Answer» B. 2mA | |
| 3161. |
A sinusoidal voltage V(t) = 100 sin (500t) is applied across a pure inductance of L=0.02H. The current through the coil is: |
| A. | \[10\,\cos \,(500\,t)\] |
| B. | \[-10\,\cos \,(500\,t)\] |
| C. | \[10\,\sin \,(500\,t)\] |
| D. | \[-10\,\sin \,(500\,t)\] |
| Answer» C. \[10\,\sin \,(500\,t)\] | |
| 3162. |
If\[{{i}_{1}}=3\,\sin \,\omega t\]and\[{{i}_{2}}=4\,\cos \,\omega t\], then\[{{i}_{3}}\]is |
| A. | \[5\,\sin \,(\omega t+{{53}^{o}})\] |
| B. | \[5\,\sin \,(\omega t+{{37}^{o}})\] |
| C. | \[5\,\sin \,(\omega t+{{45}^{o}})\] |
| D. | \[5\,\cos \,(\omega t+{{53}^{o}})\] |
| Answer» B. \[5\,\sin \,(\omega t+{{37}^{o}})\] | |
| 3163. |
If an LCR series circuit is connected to an ac source, then at resonance the |
| A. | voltage across R is zero |
| B. | voltage across R equals the applied voltage |
| C. | voltage across C is zero |
| D. | voltage across L equals the applied voltage |
| Answer» C. voltage across C is zero | |
| 3164. |
The velocity of a body at time t = 0 is \[10\sqrt{2}\] m/s in the north-east direction and it is moving with an acceleration of 2 m/s2 directed towards the south. The magnitude and direction of the velocity of the body after 5 sec will be [AMU (Engg.) 1999] |
| A. | 10 m/s, towards east |
| B. | 10 m/s, towards north |
| C. | 10 m/s, towards south |
| D. | 10 m/s, towards north-east |
| Answer» B. 10 m/s, towards north | |
| 3165. |
A ball of mass m moves with speed v and it strikes normally with a wall and reflected back normally, if its time of contact with wall is t then find force exerted by ball on wall [BCECE 2005] |
| A. | \[\frac{2mv}{t}\] |
| B. | \[\frac{mv}{t}\] |
| C. | \[mvt\] |
| D. | \[\frac{mv}{2t}\] |
| Answer» B. \[\frac{mv}{t}\] | |
| 3166. |
With what minimum acceleration can a fireman slides down a rope while breaking strength of the rope is \[\frac{2}{3}\] of his weight [CPMT 1979] |
| A. | \[\frac{2}{3}g\] |
| B. | g |
| C. | \[\frac{1}{3}g\] |
| D. | Zero |
| Answer» D. Zero | |
| 3167. |
If a body of mass m is carried by a lift moving with an upward acceleration a, then the forces acting on the body are (i) the reaction R on the floor of the lift upwards (ii) the weight mg of the body acting vertically downwards. The equation of motion will be given by [MNR 1998] |
| A. | \[R=mg-ma\] |
| B. | \[R=mg+ma\] |
| C. | \[R=ma-mg\] |
| D. | \[R=mg\times ma\] |
| Answer» C. \[R=ma-mg\] | |
| 3168. |
N bullets each of mass m kg are fired with a velocity \[v\,m{{s}^{-1}}\] at the rate of n bullets per second upon a wall. The reaction offered by the wall to the bullets is given by |
| A. | nmv |
| B. | \[\frac{Nmv}{n}\] |
| C. | \[n\frac{Nm}{v}\] |
| D. | \[n\frac{Nv}{m}\] |
| Answer» B. \[\frac{Nmv}{n}\] | |
| 3169. |
A thief stole a box full of valuable articles of weight W and while carrying it on his back, he jumped down a wall of height ?h? from the ground. Before he reached the ground he experienced a load of [NCERT 1973] |
| A. | 2W |
| B. | W |
| C. | W/2 |
| D. | Zero |
| Answer» E. | |
| 3170. |
A body of mass m collides against a wall with a velocity v and rebounds with the same speed. Its change of momentum is [Kerala PMT 2004] |
| A. | 2 mv |
| B. | mv |
| C. | ? mv |
| D. | Zero |
| Answer» B. mv | |
| 3171. |
When the speed of a moving body is doubled [UPSEAT 2004] |
| A. | Its acceleration is doubled |
| B. | Its momentum is doubled |
| C. | Its kinetic energy is doubled |
| D. | Its potential energy is doubled |
| Answer» C. Its kinetic energy is doubled | |
| 3172. |
A force of 100 dynes acts on a mass of 5 gram for 10 sec. The velocity produced is [Pb. PET 2004] |
| A. | \[2000\,\,cm/\sec \] |
| B. | \[200\,\,cm/\sec \] |
| C. | \[20\,\,cm/\sec \] |
| D. | \[2\,\,cm/\sec \] |
| Answer» C. \[20\,\,cm/\sec \] | |
| 3173. |
A man of weight 80 kg is standing in an elevator which is moving with an acceleration of \[6\,\,m/{{s}^{2}}\] in upward direction. The apparent weight of the man will be \[(g=10\,m/{{s}^{2}})\] [DPMT 2003] |
| A. | 1480 N |
| B. | 1280 N |
| C. | 1380 N |
| D. | None of these |
| Answer» C. 1380 N | |
| 3174. |
In the above problem if the lift moves up with an acceleration equal to the acceleration due to gravity, the reading on the spring balance will be [NCERT 1977] |
| A. | 2 kg |
| B. | \[(2\times g)\,kg\] |
| C. | \[(4\times g)\,kg\] |
| D. | 4 kg |
| Answer» E. | |
| 3175. |
There is a simple pendulum hanging from the ceiling of a lift. When the lift is stand still, the time period of the pendulum is T. If the resultant acceleration becomes \[g/4,\] then the new time period of the pendulum is [DCE 2004] |
| A. | 0.8 T |
| B. | 0.25 T |
| C. | 2 T |
| D. | 4 T |
| Answer» D. 4 T | |
| 3176. |
The spring balance inside a lift suspends an object. As the lift begins to ascent, the reading indicated by the spring balance will [DCE 2003] |
| A. | Increase |
| B. | Decrease |
| C. | Remain unchanged |
| D. | Depend on the speed of ascend |
| Answer» B. Decrease | |
| 3177. |
The linear momentum p of a body moving in one dimension varies with time according to the equation \[p=a+b{{t}^{2}}\] where a and b are positive constants. The net force acting on the body is [Pb. PET 2002] |
| A. | A constant |
| B. | Proportional to \[{{t}^{2}}\] |
| C. | Inversely proportional to t |
| D. | Proportional to t |
| Answer» E. | |
| 3178. |
The adjacent figure is the part of a horizontally stretched net. section AB is stretched with a force of 10 N. The tensions in the sections BC and BF are [KCET 2005] |
| A. | 10 N, 11 N |
| B. | 10 N, 6 N |
| C. | 10 N, 10 N |
| D. | Can't calculate due to insufficient data |
| Answer» D. Can't calculate due to insufficient data | |
| 3179. |
A man of weight 75 kg is standing in an elevator which is moving with an acceleration of \[5\,m/{{s}^{2}}\] in upward direction the apparent weight of the man will be \[(g=10\,\,m/{{s}^{2}})\] [Pb. PMT 2004] |
| A. | 1425 N |
| B. | 1375 N |
| C. | 1250 N |
| D. | 1125 N |
| Answer» E. | |
| 3180. |
An automobile travelling with a speed of \[60\,\,km/h,\] can brake to stop within a distance of 20 m. If the car is going twice as fast, i.e. 120 km/h, the stopping distance will be [AIEEE 2004] |
| A. | 20 m |
| B. | 40 m |
| C. | 60 m |
| D. | 80 m |
| Answer» E. | |
| 3181. |
A machine gun fires a bullet of mass 40 g with a velocity \[1200\,\,m{{s}^{-1}}.\] The man holding it can exert a maximum force of 144 N on the gun. How many bullets can he fire per second at the most [AIEEE 2004] |
| A. | One |
| B. | Four |
| C. | Two |
| D. | Three |
| Answer» E. | |
| 3182. |
A body of mass 2 kg has an initial velocity of 3 meters per second along OE and it is subjected to a force of 4 N in a direction perpendicular to OE. The distance of the body from O after 4 seconds will be [CPMT 1976] |
| A. | 12 m |
| B. | 20 m |
| C. | 8 m |
| D. | 48 m |
| Answer» C. 8 m | |
| 3183. |
A block of mass m is placed on a smooth wedge of inclination \[\theta \]. The whole system is accelerated horizontally so that the block does not slip on the wedge. The force exerted by the wedge on the block (g is acceleration due to gravity) will be [CBSE PMT 2004] |
| A. | \[mg\cos \theta \] |
| B. | \[mg\sin \theta \] |
| C. | \[mg\] |
| D. | \[mg/\cos \theta \] |
| Answer» E. | |
| 3184. |
Mass of a person sitting in a lift is 50 kg. If lift is coming down with a constant acceleration of 10 \[m/se{{c}^{2}}.\] Then the reading of spring balance will be \[(g=10m/se{{c}^{2}})\] [RPET 2003; Kerala PMT 2005] |
| A. | 0 |
| B. | 1000N |
| C. | 100 N |
| D. | 10 N |
| Answer» B. 1000N | |
| 3185. |
In the above problem, if the lift moves up with a constant velocity of 2 m/sec, the reading on the balance will be [NCERT 1977] |
| A. | 2 kg |
| B. | 4 kg |
| C. | Zero |
| D. | 1 kg |
| Answer» B. 4 kg | |
| 3186. |
A plumb line is suspended from a ceiling of a car moving with horizontal acceleration of a. What will be the angle of inclination with vertical [Orissa JEE 2003] |
| A. | \[{{\tan }^{-1}}(a/g)\] |
| B. | \[{{\tan }^{-1}}(g/a)\] |
| C. | \[{{\cos }^{-1}}(a/g)\] |
| D. | \[{{\cos }^{-1}}(g/a)\] |
| Answer» B. \[{{\tan }^{-1}}(g/a)\] | |
| 3187. |
A rocket with a lift- off mass \[3.5\times {{10}^{4}}\]\[kg\] is blasted upwards with an initial acceleration of \[10m/{{s}^{2}}.\] Then the initial thrust of the blast is [AIEEE 2003] |
| A. | \[1.75\times {{10}^{5}}N\] |
| B. | \[3.5\times {{10}^{5}}N\] |
| C. | \[7.0\times {{10}^{5}}N\] |
| D. | \[14.0\times {{10}^{5}}N\] |
| Answer» D. \[14.0\times {{10}^{5}}N\] | |
| 3188. |
A spring balance is attached to the ceiling of a lift. A man hangs his bag on the spring and the spring reads 49 N, when the lift is stationary. If the lift moves downward with an acceleration of \[5\,m/{{s}^{2}},\] the reading of the spring balance will be [AIEEE 2003] |
| A. | 49 N |
| B. | 24 N |
| C. | 74 N |
| D. | 15 N |
| Answer» C. 74 N | |
| 3189. |
If in a stationary lift, a man is standing with a bucket full of water, having a hole at its bottom. The rate of flow of water through this hole is \[{{R}_{0}}.\] If the lift starts to move up and down with same acceleration and then that rates of flow of water are \[{{R}_{u}}\] and \[{{R}_{d}},\] then [UPSEAT 2003] |
| A. | \[{{R}_{0}}>{{R}_{u}}>{{R}_{d}}\] |
| B. | \[{{R}_{u}}>{{R}_{0}}>{{R}_{d}}\] |
| C. | \[{{R}_{d}}>{{R}_{0}}>{{R}_{u}}\] |
| D. | \[{{R}_{u}}>{{R}_{d}}>{{R}_{0}}\] |
| Answer» C. \[{{R}_{d}}>{{R}_{0}}>{{R}_{u}}\] | |
| 3190. |
A monkey of mass 20kg is holding a vertical rope. The rope will not break when a mass of 25 kg is suspended from it but will break if the mass exceeds 25 kg. What is the maximum acceleration with which the monkey can climb up along the rope \[(g=10m/{{s}^{2}})\] [CBSE PMT 2003] |
| A. | \[10\,m/{{s}^{2}}\] |
| B. | \[25\,m/{{s}^{2}}\] |
| C. | \[2.5m/{{s}^{2}}\] |
| D. | \[5m/{{s}^{2}}\] |
| Answer» D. \[5m/{{s}^{2}}\] | |
| 3191. |
A man weighs \[80kg.\] He stands on a weighing scale in a lift which is moving upwards with a uniform acceleration of \[5m/{{s}^{2}}.\] What would be the reading on the scale. \[(g=10m/{{s}^{2}})\] [CBSE PMT 2003] |
| A. | 400 N |
| B. | 800 N |
| C. | 1200 N |
| D. | Zero |
| Answer» D. Zero | |
| 3192. |
A lift accelerated downward with acceleration 'a'. A man in the lift throws a ball upward with acceleration \[{{a}_{0}}({{a}_{0}} |
| A. | \[(a+{{a}_{0}})\] upward |
| B. | \[(a-{{a}_{0}})\] upward |
| C. | \[(a+{{a}_{0}})\] downward |
| D. | \[(a-{{a}_{0}})\] downward |
| Answer» E. | |
| 3193. |
A lift is moving down with acceleration a. A man in the lift drops a ball inside the lift. The acceleration of the ball as observed by the man in the lift and a man standing stationary on the ground are respectively [AIEEE 2002] |
| A. | \[g,\,g\] |
| B. | \[g-a,\,g-a\] |
| C. | \[g-a,\,g\] |
| D. | \[a,\,g\] |
| Answer» D. \[a,\,g\] | |
| 3194. |
A lift of mass 1000 kg is moving with an acceleration of 1 \[m/{{s}^{2}}\] in upward direction. Tension developed in the string, which is connected to the lift, is [CBSE PMT 2002] |
| A. | 9,800 N |
| B. | 10,000 N |
| C. | 10,800 N |
| D. | 11,000 N |
| Answer» D. 11,000 N | |
| 3195. |
A block of mass \[5\,kg\] is moving horizontally at a speed of 1.5 m/s. A perpendicular force of 5N acts on it for 4 sec. What will be the distance of the block from the point where the force started acting [Pb. PMT 2002] |
| A. | 10 m |
| B. | 8 m |
| C. | 6 m |
| D. | 2 m |
| Answer» B. 8 m | |
| 3196. |
A body of mass 2 kg is hung on a spring balance mounted vertically in a lift. If the lift descends with an acceleration equal to the acceleration due to gravity ?g?, the reading on the spring balance will be [NCERT 1977] |
| A. | 2 kg |
| B. | \[(4\times g)\,kg\] |
| C. | \[(2\times g)\,kg\] |
| D. | Zero |
| Answer» E. | |
| 3197. |
A boy whose mass is 50kg stands on a spring balance inside a lift. The lift starts to ascent with an acceleration of \[2m{{s}^{-2}}.\] The reading of the machine or balance \[(g=10\,m{{s}^{-2}})\]is [Kerala PET 2002] |
| A. | \[50\,kg\] |
| B. | Zero |
| C. | \[49\,kg\] |
| D. | \[60\,kg\] |
| Answer» E. | |
| 3198. |
A rocket is ejecting \[50g\] of gases per sec at a speed of \[500\,m/s.\] The accelerating force on the rocket will be [Pb. PMT 2002] |
| A. | \[125\,N\] |
| B. | \[25\,N\] |
| C. | \[5\,N\] |
| D. | Zero |
| Answer» C. \[5\,N\] | |
| 3199. |
If rope of lift breaks suddenly, the tension exerted by the surface of lift [AFMC 2002] (a = acceleration of lift) |
| A. | mg |
| B. | \[m\,(g+a)\] |
| C. | \[m(g-a)\] |
| D. | \[0\] |
| Answer» E. | |
| 3200. |
A player caught a cricket ball of mass 150 gm moving at the rate of 20 m/sec. if the catching process be completed in 0.1 sec the force of the blow exerted by the ball on the hands of player is [Kerala PET 2005] |
| A. | 0.3 N |
| B. | 30 N |
| C. | 300 N |
| D. | 3000 N |
| Answer» C. 300 N | |