Semiconductor Electronic: Material, Devices And Simple Circuits — Physics STD 12 Science — Question

The energy stored per unit volume of a space is called as:

Displacement current goes through the gap between the plates of a capacitor when the charge of the capacitor:

If frequency of the incident photon on the metal surface is made double, then kinetic energy of the emitted photoelectron will become :

The electromagnetic waves of frequency 2 MHz to 30 MHz are

(a) In ground wave propagation	(b) In sky wave propagation
(c) In microwave propagation	(d) In satellite communication

A thin equiconvex lens is made of glass of refractive index 1.5 and its focal length is 0.2 m, if it acts as a concave lens of 0.5 m focal length when dipped in a liquid, the refractive index of the liquid is

(a)

(b)

(c)

(d)

A photon of  1.7  Joules is absorbed by a material under special circumstances. The correct statement is

(a) Electrons of the atom of absorbed material will go the higher energy states

(b) Electron and positron pair will be created

(c) Only positron will be produced

(d) Photoelectric effect will occur and electron will be produced

A solid conducting sphere of radius a has a net positive charge 2Q. A conducting spherical shell of inner radius  b and outer radius c is concentric with the solid sphere and has a net charge – Q. The surface charge density on the inner and outer surfaces of the spherical shell will be

(a)

(b)

(c) 0,

(d) None of the above

What is the driving force in a working Electrical Circuit?

The conductivity of a metal decreases with the increase in temperature on account of:

When  ampere current is passed in a tangent galvanometer, there is a deflection of 30° in it. The deflection obtained when 3 amperes current is passed, is

(a) 30°

(b) 45°

(c) 60°

(d) 75°