(English Medium) ICSE Class 10 - CISCE Important Questions

What are free electrons?

Why do Free electrons not leave the metal surface on their own

How can they be made to leave the metal surface? (State any two ways)

An element `""_ZS^A` decays to `""_85R^222` after emitting 2 α particles and 1 β particle.

Find the atomic number and atomic mass of the element S.

A radioactive substance is oxidized. Will there be any change in the nature its radioactivity? Give a reason for your answer

Arrange α, β, and γ rays in ascending order with respect to their

1) Penetrating power.

2) Ionising power

3) Biological effect

In a cathode ray tube, what is the function of anode?

State the energy conversion taking place in a cathode ray tube

Write one use of cathode ray tube.

Represent the change in the nucleus of a radioactive element when a β particle is emitted.

Under which conditions does the nucleus of an atom tend to radioactive?

Why is a cathode ray tube evacuated to a low pressure?

What happens if the negative potential is changed on a grid?

Name a gas caused by the Greenhouse effect

What is thermionic emission?

Name the unit in which the work function of a metal is expressed.

Complete the diagram as given above by drawing the deflection of radioactive radiations in an electric field

State any two precautions to be taken while handling radioactive substances.

A nucleus `""_11^24Na`  emits a beta particle to change into Magnesium (Mg)

(i) Write the symbolic equation for the process.
(ii) What are numbers 24 and 11 called?
(iii) What is the general name of `""_12^24Mg `with respect to `""_11^24Na` ?

In a cathode ray tube state:
(i) the purpose of covering cathode by thorium and carbon.
(ii) the purpose of the fluorescent screen.
(iii) how is it possible to increase the rate of emission of electrons.