The mutual inductance between two coils is 1.25 henry. If the current in the primary changes at the rate of 80 ampere/second, then the induced e.m.f. in the secondary is
|
(a) 12.5 V |
(b) 64.0 V |
(c) 0.016 V |
(d) 100.0 V |
(d) 100.0 V
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Five capacitors of 10 μF capacity each are connected to a d.c. potential of 100 volts as shown in the adjoining figure. The equivalent capacitance between the points A and B will be equal to
|
(a) 40 μF |
(b) 20 μF |
(c) 30 μF |
(d) 10 μF |
The alloys constantan and manganin are used to make standard resistance due to they have
|
(a) Low resistivity |
(b) High resistivity |
|
(c) Low temperature coefficient of resistance |
(d) Both (b) and (c) |
A narrow electron beam passes undeviated through an electric field E = 3 
and an overlapping magnetic field B = 2 
. If electric field and magnetic field are mutually perpendicular. The speed of the electrons is
|
(a) 60 m/s |
(b) 10.3 |
(c) 1.5 |
(d) 0.67 |
A charge q is moving in a magnetic field then the magnetic force does not depend upon
|
(a) Charge |
(b) Mass |
(c) Velocity |
(d) Magnetic field |
The figure shows a graph between ln
and ln|n|, where 
is the area enclosed by the nth orbit in a hydrogen like atom. The correct curve is
|
(a) 4 |
(b) 3 |
(c) 2 |
(d) 1 |
The ratio of the largest to shortest wavelengths in Lyman series of hydrogen spectra is
|
(a) |
(b) |
(c) |
(d) |
Assertion : When PN-junction is forward biased then motion of charge carriers at junction is due to diffusion. In reverse biasing. The cause of motion of charge is drifting.
Reason : In the following circuit emitter is reverse biased and collector is forward biased.
|
(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. |
Drift velocity 
varies with the intensity of electric field as per the relation
|
(a) |
(b) |
(c) |
(d) |
