If the thermionic current density is J and emitter temperature is T then the curve between 
and 
will be
(a)
|
(b)
|
(c)
|
(d)
|
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The expression for thermo e.m.f. in a thermocouple is given by the relation E = 40 θ - 
, where θ is the temperature difference of two junctions. For this, the neutral temperature will be
|
(a) 100℃ |
(b) 200℃ |
(c) 300℃ |
(d) 400℃ |
Silver and copper voltameter are connected in parallel with a battery of e.m.f. 12 V. In 30 minutes, 1 gm of silver and 1.8 gm of copper are liberated. The power supplied by the battery is (
and 
|
(a) 24.13 J/sec |
(b) 2.413 J/sec |
(c) 0.2413 J/sec |
(d) 2413 J/sec |
The correct curve between the stopping potential (V) and intensity of incident light (I) is
|
(a)
|
(b)
|
(c)
|
(d)
|
The colour of the positive column in a gas discharge tube depends on
|
(a) The type of glass used to construct the tube |
(b) The gas in the tube |
|
(c) The applied voltage |
(d) The material of the cathode |
In comparison to a half wave rectifier, the full wave rectifier gives lower
|
(a) Efficiency |
(b) Average dc |
|
(c) Average output voltage |
(d) None of these |
If fa and ff represent the carrier wave frequencies for amplitude and frequency modulations respectively, then
|
(a) |
(b) |
(c) |
(d) |
