A bar magnet of magnetic moment M is placed at right angles to a magnetic induction B. If a force F is experienced by each pole of the magnet, the length of the magnet will […]
A particle of mass ‘m’ is kept at rest at a height 3R from the surface of earth, where ‘R’ is radius of earth and ‘M’ is mass of earth. The minimum speed with which […]
The radius of a planet is twice the radius of earth. Both have almost equal average mass densities. If Vp and Ve are escape velocities of the planet and the earth, respectively, then,
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Two sources P and Q produce notes of frequency 660 Hz each. A listener moves from P to Q with a speed of 1 ms⁻¹. If the speed of sound is 330 m/s, then the […]
Two Carnot engine A and B are operated in series. The engine A receives that heat from the source at temperature T₁ and rejects the heat to the sink at temperature T. The second engine […]
An electric dipole of dipole moment p is aligned parallel to a uniform electric field E. The energy required to rotate the dipole by 90⁰ is
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(a) p E² (b) p² E […]
One way in which the operation of a n-p-n transistor differs from that of a p-n-p
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(a) the emitter junction is reserved biased in n-p-n (b) the emitter junction injects minority carriers […]
In an unbiased p-n junction, holes diffuse from the p-region to n-region because of
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(a) the potential difference across the p-n junction (b) the attraction of free electrons of n-region (c) the […]
The de-Broglie wavelength of neutron in thermal equilibrium at temperature T is
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(a) 30.8 / √T Å (b) 3.08 / √T Å (c) 0.308 / √T Å (d) 0.0308 / √T Å
A source of light is placed at a distance of 50 cm from a photocell and the stopping potential is found to be V₀. If the distance between the light source and photocell is made […]
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