On adjusting the P-N junction diode in forward biased
|
(a) Depletion layer increases |
(b) Resistance increases |
|
(c) Both decreases |
(d) None of these |
(c) Both decreases
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The heat developed in an electric wire of resistance R by a current I for a time t is
|
(a) |
(b) |
(c) |
(d) |
The current passing through a choke coil of 5 henry is decreasing at the rate of 2 ampere/sec. The e.m.f. developing across the coil is
|
(a) 10 V |
(b) – 10 V |
(c) 2.5 V |
(d) – 2.5 V |
A nucleus ruptures into two nuclear parts which have their velocity ratio equal to 2 : 1. What will be the ratio of their nuclear size (nuclear radius)
|
(a) |
(b) 1 : |
(c) |
(d) 1 : |
An electric charge q is placed at the centre of a cube of side α. The electric flux on one of its faces will be
|
(a) |
(b) |
(c) |
(d) |
A radioactive substance has an average life of 5 hours. In a time of 5 hours
|
(a) Half of the active nuclei decay |
(b) Less than half of the active nuclei decay |
|
(c) More than half of the active nuclei decay |
(d) All active nuclei decay |
The work done in bringing a 20 coulomb charge from point A to point B for distance 0.2m is 2J. The potential difference between the two points will be (in volt)
|
(a) 0.2 |
(b) 8 |
(c) 0.1 |
(d) 0.4 |
Between the primary and secondary rainbows, there is a dark band known as Alexandar’s dark band. This is because:
Activity of radioactive element decreased to one third of original activity 
in 9 years. After further 9 years, its activity will be
|
(a)
|
(b) 
|
(c) |
(d) |
