- AMechanical energy
- BNuclear energy
- ✓Thermonuclear energy
- DElectromagnetic energy.
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An ellipsoidal cavity is carved within a perfect conductor. A positive charge q is placed at the centre of the cavity. The points A and B are on the cavity surface as shown in the figure. Then
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(a) Potential at A = Potential at B |
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(b) Total electric field flux through the surface of the cavity is q/ |
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(c) Electric field near A in the cavity = Electric field near B in the cavity |
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(d) a, b |
Which one of the following statements is correct
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(a) In vacuum, the speed of light depends upon frequency |
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(b) In vacuum, the speed of light does not depend upon frequency |
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(c) In vacuum, the speed of light is independent of frequency and wavelength |
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(d) In vacuum, the speed of light depends upon wavelength |
Smaller pieces of heavy stones and metals which on entering earth's atmosphere burns out are
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(a) Comets |
(b) Meteorites |
(c) Asteroids |
(d) All of these |
The magnetic induction at a point P which is distant 4 cm from a long current carrying wire is
. The field of induction at a distance 12 cm from the same current would be
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(a) 3.33 |
(b) 1.11 |
(c) 3 |
(d) 9 |
The current is flowing in south direction along a power line. The direction of magnetic field above the power line (neglecting earth's field) is
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(a) South |
(b) East |
(c) North |
(d) West |
The critical angle for diamond (refractive index = 2) is
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(a) About 20° |
(b) 60° |
(c) 45° |
(d) 30° |
Electronic configuration of germanium is 2, 8, 18 and 4. To make it extrinsic semiconductor small quantity of antimony is added
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(a) The material obtained will be N-type germanium in which electrons and holes are equal in number |
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(b) The material obtained will be P-type germanium |
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(c) The material obtained will be N-type germanium which has more electrons than holes at room temperature |
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(d) The material obtained will be N-type germanium which has less electrons than holes at room temperature |
After 1α and 2β emissions
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(a) Mass number reduces by 3 |
(b) Mass number reduces by 4 |
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(c) Mass number reduces by 6 |
(d) Atomic number remains unchanged |
Two bulbs of 100 W and 200 W working at 220 volt are joined in series with 220 volt supply. Total power consumed will be approximately.
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(a) 65 watt |
(b) 33 watt |
(c) 300 watt |
(d) 100 watt |