Electric Charges and Fields — Physics STD 12 Science — Question

Which of the following diagrams, shows correctly the dispersion of white light by a prism

(a)

(b)

(c)

(d)

Fraunhofer lines of the solar system is an example of

(a) Emission spectrum	(b) Emission band spectrum
(c) Continuous emission spectrum	(d) Line absorption spectrum

Gases exert pressure on the walls of the container, because the gas molecules:

Like coulomb force, ______ also satisfies superposition principle.

A solid sphere, a hollow sphere and a disc, all having same mass and radius, are placed at the top of a smooth incline and released. Least time will be taken in reaching the bottom by:

1. The solid sphere.
2. The hollow sphere.
3. The disc.
4. All will take same time.

A radioactive substance has a half life of 60 minutes. After 3 hours, the fraction of atom that have decayed would be

(a)12.5%

(b) 87.5%

(c) 8.5%

(d) 25.1%

Plane polarised light is passed through a polaroid. On viewing through the polaroid we find that when the polariod is given one complete rotation about the direction of the light, one of the following is observed

(a) The intensity of light gradually decreases to zero and remains at zero

(b) The intensity of light gradually increases to a maximum and remains at maximum

(c) There is no change in intensity

(d) The intensity of light is twice maximum and twice zero

In the circuit shown in figure, the heat produced in 5 ohm resistance is 10 calories per second. The heat produced in 4 resistance is

(a) 1 cal / sec

(b) 2 cal/sec

(c) 3 cal / sec

(d) 4 cal/sec

Modern atomic mass scale is based on the mass of:

Critical mass is minimum mass necessary for: