Dual Nature of Radiation and Matter — Physics STD 12 Science — Question

The length of a given cylindrical wire is increased by 100 %.  Due to the consequent decrease in diameter the change in the resistance of the wire will be

(a) 300 %

(b) 200 %

(c) 100 %

(d) 50 %

Two identical short bar magnets, each having magnetic moment of 10 Am², are arranged such that their axial lines are perpendicular to each other and their centres be along the same straight line in a horizontal plane. If the distance between their centres is 0.2 m, the resultant magnetic induction at a point  midway between them  is ( 

(a)  Tesla

(b)  Tesla

(c)  Tesla

(d)  Tesla

Which of the following are suitable for the fusion process

(a) Heavy nuclei

(b) Light nuclei

(c) Atom bomb

(d) Radioactive decay

The nature of charge on the object can be detected by:

A small sphere carrying a charge ‘q’ is hanging in between two parallel plates by a string of length L. Time period of pendulum is . When parallel plates are charged, the time period changes to T . The ratio   is equal to

(a)

(b)

(c)

(d) None of these

Mutual inductance of two coils can be increased by

(a) Decreasing the number of turns in the coils

(b) Increasing the number of turns in the coils

(c) Winding the coils on wooden core

(d) None of the above

Consider an electron (m = 9.1   confined by electrical forces to move between two rigid walls separated by 1.0  metre, which is about five atomic diameters. The quantised energy value for the lowest stationary state is

(a) 12

(b) 6.0

(c) 6.0

(d) 6 Joule

A resistor of resistance R is connected to an ideal battery. If the value of R is decreased, the power dissipated in the resistor will:

1. Increase.
2. Decrease.
3. Remain unchanged.

Fusion reaction takes place at very high temperature because:

In Fig, Vo is the potential barrier across a p-n junction, when no battery is connected across the junction: