The cathode of a photoelectric cell is changed such that the work function changes from W1 to W2 (W2>W1). If the current before and after change are I1 and I2, all other conditions remaining unchanged, then (assuming hn > W2)
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(a) |
(b) |
(c) |
(d) |
(a) 
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The electric field at a point on equatorial line of a dipole and direction of the dipole moment
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(a) Will be parallel |
(b) Will be in opposite direction |
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(c) Will be perpendicular |
(d) Are not related |
Assertion : A double convex lens (m = 1.5) has focal length 10 cm. When the lens is immersed in water (m = 4/3) its focal length becomes 40 cm.
Reason : 
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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. |
Two identical short bar magnets, each having magnetic moment of 10 Am2, are arranged such that their axial lines are perpendicular to each other and their centres be along the same straight line in a horizontal plane. If the distance between their centres is 0.2 m, the resultant magnetic induction at a point midway between them is (
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(a) |
(b) |
(c)  Tesla
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(d)  Tesla
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Energy stored in electromagnetic oscillations is in the form of
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(a) Electrical energy |
(b) Magnetic energy |
(c) Both (a) and (b) |
(d) None of these |
Indicate which one of the following system is digital
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(a) Pulse position modulation |
(b) Pulse code modulation |
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(c) Pulse width modulation |
(d) Pulse amplitude modulation |
