A resistor 
dissipates the power P when connected to a certain generator. If the resistor 
is put in series with , the power dissipated by
|
(a) Decreases |
|
(b) Increases |
|
(c) Remains the same |
|
(d) Any of the above depending upon the relative values of |
(a) Decreases
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A metal conductor of length 1m rotates vertically about one of its ends at angular velocity 5 radians per second. If the horizontal component of earth's magnetic field is 0.2 
, then the e.m.f. developed between the two ends of the conductor is
|
(a) 5mV |
(b) 5 |
(c) 50 mV |
(d) 50 μV |
The equivalent resistance between the points P and Q of the circuit given is
|
(a) |
(b) |
(c) 4 R |
(d) 2 R |
Which of the following is not reversible
|
(a) Joule effect |
(b) Peltier effect |
(c) Seebeck effect |
(d) Thomson effect |
A 10 m long wire of 20W resistance is connected with a battery of 3 volt e.m.f. (negligible internal resistance) and a 10 W resistance is joined to it is series. Potential gradient along wire in volt per meter is
|
(a) 0.02 |
(b) 0.3 |
(c) 0.2 |
(d) 1.3 |
Spherical aberration in a lens
|
(a) Is minimum when most of the deviation is at the first surface |
|
(b) Is minimum when most of the deviation is at the second surface |
|
(c) Is minimum when the total deviation is equally distributed over the two surface |
|
(d) Does not depend on the above consideration |
A source emits light of wavelength 4700Å, 5400 Å and 6500 Å. The light passes through red glass before being tested by a spectrometer. Which wavelength is seen in the spectrum
|
(a) 6500 Å |
(b) 5400 Å |
(c) 4700 Å |
(d) All the above |
If the critical angle for total internal reflection from a medium to vacuum is 30°, the velocity of light in the medium is
|
(a) 3 |
(b) 1.5 |
(c) 6 |
(d) |
