Doppler's effect in sound in addition to relative velocity between source and observer, also depends while source and observer or both are moving. Doppler effect in light depend only on the relative velocity of source and observer. The reason of this is
|
(a) Einstein mass - energy relation |
(b) Einstein theory of relativity |
|
(c) Photoelectric effect |
(d) None of these |
(b) Einstein theory of relativity
Generate a complete, print-ready paper with questions like this in minutes — across 16+ boards, with answer keys.
Sinusoidal carrier voltage of frequency 1.5 MHz and amplitude 50 V is amplitude modulated by sinusoidal voltage of frequency 10 kHz producing 50% modulation. The lower and upper side-band frequencies in kHz are
|
(a) 1490, 1510 |
(b) 1510, 1490 |
(c) |
(d) |
The direction of induced current is such that it opposes the very cause that has produced it. This is the law of
|
(a) Lenz |
(b) Faraday |
(c) Kirchhoff |
(d) Fleming |
Two insulated charged conducting spheres of radii 20 cm and 15 cm respectively and having an equal charge of 10 C are connected by a copper wire and then they are separated. Then
|
(a) Both the spheres will have the same charge of 10 C |
|
(b) Surface charge density on the 20 cm sphere will be greater than that on the 15 cm sphere |
|
(c) Surface charge density on the 15 cm sphere will be greater than that on the 20 cm sphere |
|
(d) Surface charge density on the two spheres will be equal |
Assertion : Television signals are received through sky-wave propagation.
Reason : The ionosphere reflects electromagnetic waves of frequencies greater than a certain critical frequency.
|
(a) If both assertion and reason are true and the reason is the correct explanation of the assertion. |
|
(b) If both assertion and reason are true but reason is not the correct explanation of the assertion. |
|
(c) If assertion is true but reason is false. |
|
(d) If the assertion and reason both are false. |
If an ammeter is to be used in place of a voltmeter then we must connect with the ammeter a
|
(a) Low resistance in parallel |
(b) High resistance in parallel |
|
(c) High resistance in series |
(d) Low resistance in series |
