Recent questions tagged #mcq

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A conducting rod PQ of length `4l` is rotated about a point O in a uniform magnetic field `vecB . PO=l`

asked Mar 20, 2022 in 12th Physics by varun (6.7k points)

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As shown in figure after a long time the battery is disconnected and short circuiting the points A & B. The current in circuit after 2ms after the short circuit

asked Mar 20, 2022 in 12th Physics by varun (6.7k points)

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The variation of induced emf with time in a coil if a short bar magnet is moved along its axis with constant velocity

asked Mar 20, 2022 in 12th Physics by varun (6.7k points)

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A square loop of side 10 cm and resistance `2_Omega` is moved with velocity `v_o` as shown in fig. The uniform magnetic field is 3T with what speed should the loop be moved so that a steady current of 1.5 mA flows in the

asked Mar 20, 2022 in 12th Physics by varun (6.7k points)

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An inductor-resistor-battery circuit is switched on at t = 0. If the emf of battry is `epsilon` find the charge passes through the battery in one time constant

asked Mar 20, 2022 in 12th Physics by varun (6.7k points)

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A square loop of side 5 cm being moved right at a constant speed `2cms^(-1)` .The front edge of it enters in magnetic field at t = 0.Fined the induced emf in the loop at t = 1s, 5s,

asked Mar 20, 2022 in 12th Physics by varun (6.7k points)

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The time constant of a LR circuit is 20 ms The circuit is connected at t = 0 and the steady state current is found to be 4A. Find the current at 80

asked Mar 20, 2022 in 12th Physics by varun (6.7k points)

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A metal rod of length 2 m rotates vertically about one of its end with frequency 2 Hz. The horizontal component of earth's magnetic field is `3.14xx 10^(-5)` then emf developed between two ends of road

asked Mar 20, 2022 in 12th Physics by varun (6.7k points)

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In the following circuit the bulb will become suddenly bright

asked Mar 20, 2022 in 12th Physics by varun (6.7k points)

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The self inductance of a coil is 5H, a current of 1A changes to 2A within 5 sec. through the coil. The value of induced emf will

asked Mar 20, 2022 in 12th Physics by varun (6.7k points)

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Pure inductance of 3H each are connected as shown below. The equivalent inductance of the circuit

asked Mar 20, 2022 in 12th Physics by varun (6.7k points)

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A coil of inductance 300 mH and resistance `2Omega` is connected to a source of voltage 2V. The current reaches half of its steady state value

asked Mar 20, 2022 in 12th Physics by varun (6.7k points)

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If rotational velocity of a dynamo armature is doubled, then induced emf will become...What is increased in step down transformer

asked Mar 20, 2022 in 12th Physics by varun (6.7k points)

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The core of a transformer is laminated so

asked Mar 20, 2022 in 12th Physics by varun (6.7k points)

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In transformer, core is made of soft iron to

asked Mar 20, 2022 in 12th Physics by varun (6.7k points)

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An ideal transformer has 1:25 turn ratio. The peak value of the ac is 28 V. The rms ms secondary voltage is nearest

asked Mar 20, 2022 in 12th Physics by varun (6.7k points)

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A primary winding of transformer has 500 turns whereas its secondary has 5000 turns. Primary is connected to ac supply of 20V, 50Hz The secondary output

asked Mar 20, 2022 in 12th Physics by varun (6.7k points)

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A step down transformer is connected to main supply 200 V to operate a 6V, 30 w bulb. The current in primary

asked Mar 20, 2022 in 12th Physics by varun (6.7k points)

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An emf of 15 V is applied in a circuit containing 5H inductance & `10 Omega` resistance. The ratio of the currents at time `t=oo` and at t =

asked Mar 20, 2022 in 12th Physics by varun (6.7k points)

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Two coils have a mutual inductance 0.005H The current changes in a coil according to equation `I = I_O sinomegat` Where `I_O = 10 A & ω= 100 π rad s^(-1)` The maximum value of emf in second coil

asked Mar 20, 2022 in 12th Physics by varun (6.7k points)

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