When a magnetic field is applied in a direction perpendicular to the direction of cathode rays, then their
|
(a) Energy decreases |
|
(b) Energy increases |
|
(c) Momentum increases |
|
(d) Momentum and energy remain unchanged |
(d) Momentum and energy remain unchanged
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Huygen’s principle of secondary wavelets may be used to
|
(a) Find the velocity of light in vacuum |
|
(b) Explain the particle behaviour of light |
|
(c) Find the new position of the wavefront |
|
(d) Explain photoelectric effect |
One Tesla is equal to
|
(a) |
(b) |
(c) |
(d) |
In a semiconductor, the concentration of electrons is 8 
and that of the holes is 5
The semiconductor is
|
(a) P-type |
(b) N-type |
(c) Intrinsic |
(d) PNP-type |
The nucleus 
after two successive 
decays will give
|
(a) |
(b) |
(c) |
(d) |
X – rays and γ - rays of the same energies may be distinguished by
|
(a) Their velocity |
(b) Their ionising power |
|
(c) Their intensity |
(d) Method of production |
On heating a liquid, the refractive index generally
|
(a) Decreases |
|
(b) Increases or decreases depending on the rate of heating |
|
(c) Does not change |
|
(d) Increases |
The coil of dynamo is rotating in a magnetic field. The developed induced e.m.f. changes and the number of magnetic lines of force also changes. Which of the following condition is correct
|
(a) Lines of force minimum but induced e.m.f. is zero |
|
(b) Lines of force maximum but induced e.m.f. is zero |
|
(c) Lines of force maximum but induced e.m.f. is not zero |
|
(d) Lines of force maximum but induced e.m.f. is also maximum |
