Atoms — Physics STD 12 Science — Question

The photoelectric effect can be understood on the basis of

(a) The principle of superposition	(b) The electromagnetic theory of light
(c) The special theory of relativity	(d) Line spectrum of the atom

Consider a parallel plate capacitor of 10 μF  (micro-farad) with air filled in the gap between the plates. Now one half of the space between the plates is filled with a dielectric of dielectric constant 4, as shown in the figure. The capacity of the capacitor changes to

(a) 25 μF

(b) 20 μF

(c) 40 μF

(d) 5 μF

What is shape of magnet in moving coil galvanometer to make the radial magnetic field?

In an AC generator, a coil with N turns, all of the same area A and total resistance R, rotates with frequency 1rad/ s in a magnetic field B. The maximum value of emf generated in the coil is:

A sample contains 16 gm of a radioactive material, the half life of which is two days. After 32 days, the amount of radioactive material left in the sample is

(a) Less than 1 mg

(b)

(c)

(d) 1 gm

Electrons are emitted by a hot filament and are accelerated by an electric field, as shown in the figure. The two stops at the left ensure that the electron beam has a uniform cross-section.

The number of turns in a coil of wire of fixed radius is 600 and its self inductance is 108mH. The self inductance of a coil of 500 turns will be:

When a negatively charged conductor is connected to earth

For a photoelectric cell the graph showing the variation of cut of voltage (V_o) with frequency (n) of incident light is best represented by

(a)

(b)

(c)

(d)

The light when enters the human eye experiences most of the refraction while passing through

(a) Cornea

(b)  Aqueous humour

(c) Vitrous humour

(d)  Crystalline lens