A coil is wound as a transformer of rectangular cross-section. If all the linear dimensions of the transformer are increased by a factor 2 and the number of turns per unit length of the coil remain the same, the self inductance increased by a factor of
|
(a) 16 |
(b) 12 |
(c) 8 |
(d) 4 |
(c) 8
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When light enters from air to water, then its
|
(a) Frequency increases and speed decreases |
|
(b) Frequency is same but the wavelength is smaller in water than in air |
|
(c) Frequency is same but the wavelength in water is greater than in air |
|
(d) Frequency decreases and wavelength is smaller in water than in air |
In Bohr’s model, if the atomic radius of the first orbit is 
, then the radius of the fourth orbit is
|
(a) |
(b) 4 |
(c) |
(d) 16 |
If a current of 3.0 amperes flowing in the primary coil is reduced to zero in 0.001 second, then the induced e.m.f. in the secondary coil is 15000 volts. The mutual inductance between the two coils is
|
(a) 0.5 henry |
(b) 5 henry |
(c) 1.5 henry |
(d) 10 henry |
One face of a rectangular glass plate 6 cm thick is silvered. An object held 8 cm in front of the first face, forms an image 12 cm behind the silvered face. The refractive index of the glass is
|
(a) 0.4 |
(b) 0.8 |
(c) 1.2 |
(d) 1.6 |
In case of linearly polarized light, the magnitude of the electric field vector :
|
(a) Does not change with time |
|
(b) Varies periodically with time |
|
(c) Increases and decreases linearly with time |
|
(d) Is parallel to the direction of propagation |
Time period of a freely suspended magnet does not depend upon
| (a) Length of the magnet |
| (b) Pole strength of the magnet |
| (c) Horizontal component of earth's magnetic field |
| (d) Length of the suspension thread |
The field of view is maximum for
|
(a) Plane mirror |
(b) Concave mirror |
(c) Convex mirror |
(d) Cylindrical mirror |
