Explanation:
If white light is used a white centre fringe is observed, but all the other fringes have coloured edges, the blue edge being nearer the centre. Eventually the fringes overlap and a uniform white light is produced.
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A thin convex lens of focal length 10 cm is placed in contact with a concave lens of same material and of same focal length. The focal length of combination will be
|
(a) Zero |
(b) Infinity |
(c) 10 cm |
(d) 20 cm |
The resultant magnetic moment of neon atom will be
|
(a) Infinity |
(b) mB |
(c) Zero |
(d) mB/2 |
An electric heater of resistance 6 ohm is run for 10 minutes on a 120 volt line. The energy liberated in this period of time is
|
(a) 7.2 |
(b) 14.4 |
(c) 43.2 |
(d) 28.8 |
A charged particle of mass m and charge q describes circular motion of radius r in a uniform magnetic field of strength B. The frequency of revolution is
|
(a) |
(b) |
(c) |
(d) |
Energy of photon whose frequency is 
, will be
|
(a) 4.14 |
(b) 4.14 |
(c) 4.14 |
(d) 4.14 |
Before the saturation state of a diode at the plate voltages of 400 V and 200 V respectively the currents are i1 and i2 respectively. The ratio i1/i2 will be
(a) 
|
(b) 2
|
(c) 2 | (d) 1/2 |
