Two infinitely long parallel conducting plates having surface charge densities +σ and -σ respectively, are separated by a small distance. The medium between the plates is vacuum. If 
is the dielectric permittivity of vacuum, then the electric field in the region between the plates is
|
(a) 0 volts/meter |
(b) |
(c) |
(d) |
(c) 
volts/meter
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Assertion : In everyday life the Doppler’s effect is observed readily for sound waves than light waves.
Reason : Velocity of light is greater than that of sound.
|
(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. |
The distance between an object and the screen is 100 cm. A lens produces an image on the screen when placed at either of the positions 40 cm apart. The power of the lens is
|
(a) ≈ 3 dioptres |
(b) ≈ 5 dioptres |
(c) ≈ 7 diopters |
(d) ≈ 9 diopters |
A compass needle will show which one of the following directions at the earth's magnetic pole
| (a) Vertical | (b) No particular direction |
| (c) Bent at 45° to the vertical | (d) Horizontal |
The ratio of the kinetic energy to the total energy of an electron in a Bohr orbit is
|
(a) – 1 |
(b) 2 |
(c) 1 : 2 |
(d) None of these |
The curve drawn between velocity and frequency of photon in vacuum will be a
|
(a) Straight line parallel to frequency axis |
|
(b) Straight line parallel to velocity axis |
|
(c) Straight line passing through origin and making an angle of 45o with frequency axis |
|
(d) Hyperbola |
