Two identical light sources S1 and S2 emit light of same wavelength l. These light rays will exhibit interference if
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(a) Their phase differences remain constant |
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(b) Their phases are distributed randomly |
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(c) Their light intensities remain constant |
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(d) Their light intensities change randomly |
(a) Their phase differences remain constant
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A small coil C with N = 200 turns is mounted on one end of a balance beam and introduced between the poles of an electromagnet as shown in figure. The cross sectional area of coil is A= 1.0 cm2, length of arm OA of the balance beam is l = 30 cm. When there is no current in the coil the balance is in equilibrium. On passing a current I = 22 mA through the coil the equilibrium is restored by putting the additional counter weight of mass ∆m = 60 mg on the balance pan. Find the magnetic induction at the spot where coil is located.
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(a) 0.4 T |
(b) 0.3 T |
(c) 0.2 T |
(d) 0.1 T |
To make the field radial in a moving coil galvanometer
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(a) The number of turns in the coil is increased |
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(b) Magnet is taken in the form of horse-shoe |
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(c) Poles are cylindrically cut |
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(d) Coil is wounded on aluminium frame |
Lux is equal to
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(a) 1 lumen/m2 |
(b) 1 lumen/cm2 |
(c) 1 candela/m2 |
(d) 1 candela/cm2 |