The current in a self-inductance L=40 mH is to be increased uniformly from 1A to 11A in 4 ms. The emf indued in the inductor during the process is
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(a) 100 V (b) […]
In a potentiometer experiment, the balancing with a cell is at length 240 cm. On shunting the cell with a resistance of 2Ω , the balancing becomes 120 cm. The internal resistance of the cell […]
Potentiometer measures the potential difference more accurately than a voltmeter because
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(a) it does not draw current from external circuit (b) it draws a heavy current from external circuit (c) it has […]
A step-up transformer operates on a 230 V line and supplies a current of 2 A. The ratio of primary and secondary winding is 1:25. The primary current is
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(a) 12.5 A […]
A thin glass(refractive index 1.5) lens has optical power of -5D in air. Its optical power in a liquid medium with refractive index 1.6 will be
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(a) 1 D (b) (-1 D) […]
A straight conductor of length 0.4 m is moved with a speed of 7 ms⁻¹perpendicular to a magnetic field of intensity 0.9 Wbm⁻². The induced emf across the conductor is
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(a) 5.04 […]
A galvanometer having internal resistance 10Ω requires 0.01 A for a full scale deflection. To convert this galvanometer to a voltmeter of full scale deflection at 120V, we need to connect a resistance of
A bar magnet of moment M and pole strength m is cut into parts of equal lengths. The magnetic moment and pole strength of either part is
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(a) M/2, m/2 (b) M, […]
A charged particle of mass m and charge q moves along a circular path of radius r that is perpendicular to a magnetic field B. The time taken by the particle to complete one revolution […]
In Young’s double slit experiment, the ratio of maximum and minimum intensities in the fringe system is 9:1. The ratio of amplitudes of coherent sources is
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(a) (9:1) (b) (3:1) (c) (2:1) […]
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