Electroplating does not help in
|
(a) Fine finish to the surface |
(b) Shining appearance |
|
(c) Metals to become hard |
(d) Protect metal against corrosion |
(c) Metals to become hard
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A photon of wavelength 6630 Å is incident on a totally reflecting surface. The momentum delivered by the photon is equal to
|
(a) 6.63 × 10–27 kg-m/sec |
(b) 2 × 10–27 kg-m/sec |
(c) 10–27 kg-m/sec |
(d) None of these |
When a thin transparent plate of thickness t and refractive index m is placed in the path of one of the two interfering waves of light, then the path difference changes by
|
(a) (m + 1)t |
(b) (m – 1)t |
(c) |
(d) |
In the half-wave rectifier circuit shown. Which one of the following wave forms is true for 
, the output across C and D ?
(a)
|
(b)
|
(c)
|
(d)
|
Among the two interfering monochromatic sources A and B; A is ahead of B in phase by 66°. If the observation be taken from point P, such that PB – PA = l/4. Then the phase difference between the waves from A and B reaching P is
|
(a) 156° |
(b) 140° |
(c) 136° |
(d) 126° |
The capacity of a condenser in which a dielectric of dielectric constant 5 has been used, is C. If the dielectric is replaced by another with dielectric constant 20, the capacity will become
|
(a) |
(b) 4C |
(c) |
(d) 2C |
$\text{f}=\frac{\text{R}}{2}$
$\text{f}=\text{R}$
$\text{f}=-\text{R}$
$\text{f}=2\text{R}$
In a diode valve the cathode temperature must be (f = work function)
|
(a) High and ∅ should be high |
(b) High and ∅ should be low |
|
(c) Low and ∅ should be high |
(d) Low and ∅ should be high |
If a copper ring is moved quickly towards south pole of a powerful stationary bar magnet, then
|
(a) Current flows through the copper ring |
|
(b) Voltage in the magnet increase |
|
(c) Current flows in the magnet |
|
(d) Copper ring will get magnetised |
