In Young's double slit experiment, white light is used. The separation between the slits is b. The screen is at a distance d (d>> b) from the slits. Some wavelengths are missing exactly in front of one slit. These wavelengths are
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(a) λ = |
(b) λ = |
(c) λ = |
(d) a, b |
(d) a, b
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Magnetic field due to 0.1 A current flowing through a circular coil of radius 0.1 m and 1000 turns at the centre of the coil is
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(a) 2 |
(b) 4.31 |
(c) 6.28 |
(d) 9.81 |
A long thin hollow metallic cylinder of radius 'R' has a current i ampere. The magnetic induction 'B'-away from the axis at a distance r from the axis varies as shown in
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(a)
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(b)
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(c)
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(d)
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A battery of e.m.f. 3 volt and internal resistance 1.0 ohm is connected in series with copper voltameter. The current flowing in the circuit is 1.5 amperes. The resistance of voltameter will be
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(a) Zero |
(b) 1.0 ohm |
(c) 1.5 ohm |
(d) 2.0 ohm |
Formula for dispersive power is (where symbols have their usual meanings)
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(a) |
(b) |
(c) |
(d) |
The resistance of a wire of uniform diameter d and length L is R. The resistance of another wire of the same material but diameter 2d and length 4L will be
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(a) 2R |
(b) R |
(c) R/2 |
(d) R/4 |
If m is mass of electron, v its velocity, r the radius of stationary circular orbit around a nucleus with charge Ze, then from Bohr's first postulate, the kinetic energy K = 
of the electron in C.G.S. system is equal to
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(a) |
(b) |
(c) |
(d) |
