- ASpecial theory of relativity
- BGeneral theory of relativity
- CPhotoelectric effect
- DTheory of specific heats
Explanation:
In 1905, Albert Einstein extended Planck's hypothesis to explain the photoelectric effect, which is the emission of electrons by a metal surface when it is irradiated by light or more-energetic photons.
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The production of e.m.f. by maintaining a difference of temperature between the two junctions of two different metals is known as
|
(a) Joule effect |
(b) Seebeck effect |
(c) Peltier effect |
(d) Thomson effect |
The e.m.f. of a cell is E volts and internal resistance is r ohm. The resistance in external circuit is also r ohm. The p.d. across the cell will be
|
(a) E/2 |
(b) 2E |
(c) 4E |
(d) E/4 |
A laser beam of pulse power 1012 watt is focussed on an object are 10–4 cm2. The energy flux in watt/ cm2 at the point of focus is
|
(a) 1020 |
(b) 1016 |
(c) 108 |
(d) 104 |
If half life of radium is 77 days. Its decay constant in day will be
|
(a) 3 |
(b) |
(c) 1 |
(d) 6 |
Which of the following statements indicates that light waves are transverse
|
(a) Light waves can travel in vacuum |
(b) Light waves show interference |
|
(c) Light waves can be polarized |
(d) Light waves can be diffracted |
When a PN junction diode is reverse biased
|
(a) Electrons and holes are attracted towards each other and move towards the depletion region |
|
(b) Electrons and holes move away from the junction depletion region |
|
(c) Height of the potential barrier decreases |
|
(d) No change in the current takes place |