An aluminium ring B faces an electromagnet A. The current I through A can be altered
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(a) Whether I increases or decreases, B will not experience any force |
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(b) If I decrease, A will repel B |
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(c) If I increases, A will attract B |
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(d) If I increases, A will repel B |
(d) If I increases, A will repel B
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In the given circuit the current I1 is
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(a) 0.4 A |
(b) – 0.4 A |
(c) 0.8 A |
(d) – 0.8 A |
Assertion : Amongst alpha, beta and gamma rays, a-particle has maximum penetrating power.
Reason : The alpha particle is heavier than beta and gamma rays.
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(a) If both assertion and reason are true and the reason is the correct explanation of the assertion. |
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(b) If both assertion and reason are true but reason is not the correct explanation of the assertion. |
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(c) If assertion is true but reason is false. |
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(d) If the assertion and reason both are false. |
A uniform magnetic field acts at right angles to the direction of motion of electrons. As a result, the electron moves in a circular path of radius 2 cm. If the speed of the electrons is doubled, then the radius of the circular path will be
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(a) 2.0 cm |
(b) 0.5 cm |
(c) 4.0 cm |
(d) 1.0 cm |
A convex mirror has a focal length f. A real object is placed at a distance f in front of it from the pole produces an image at
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(a) Infinity |
(b) f |
(c) f/2 |
(d) 2f |
For the structural analysis of crystals, X-rays are used because
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(a) X-rays have wavelength of the order of interatomic spacing |
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(b) X-rays are highly penetrating radiations |
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(c) Wavelength of X-rays is of the order of nuclear size |
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(d) X-rays are coherent radiations |