Current Electricity — Physics STD 12 Science — Question

The purpose of cathode in cathode ray tube is ______:

Nucleus of an atom whose atomic mass is 24 consists of

(a) 11 electrons, 11 protons and 13 neutrons	(b) 11 electrons, 13 protons and 11 neutrons
(c) 11 protons and 13 neutrons	(d) 11 protons and 13 electrons

The temperature bellow which a material becomes a superconductor is called:

A cylindrical conductor has uniform cross-section. Resistivity of its material increase linearly from left end to right end. If a constant current is flowing through it and at a section distance x from left end, magnitude of electric field intensity is E, which of the following graphs is correct

(a)

(b)

(c)

(d)

When water droplets merge to form a bigger drop:

1. Energy is liberated.
2. Energy is absorbed.
3. Energy is neither liberated nor absobred.
4. Energy may either be liberated or absorbed depending on the nature of the liquid.

Yellow light is used in single slit diffraction experiment with slit width 0.6 mm. If yellow light is replaced by X-rays then the pattern will reveal

(a) That the central maxima is narrower	(b) No diffraction pattern
(c) More number of fringes	(d) Less number of fringes

The current between B and D in the given figure is

(a) 1 amp

(b) 2 amp

(c) Zero

(d) 0.5 amp

In a semiconductor diode, the barrier potential offers opposition to:

According to Maxwell , most of the optical properties of light depend on: