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Daily Practice Problems
Class 12 Physics
Nuclei
daily practice problem

Question 1:

A radioactive nucleus emits a beta particle, then the parent and daughter nuclei are

(a) isotones

(b) isotopes

(c) isomers

(d) isobars

 

Question 2:

Sun’s radiant energy is due to

(a) nuclear Fusion

(b) nuclear Fission

(c) photoelectric Effect

(d) radioactive Decay

 

Question 3:

The discovery of Neutron is done by:

(a) J.J Thomson

(b) James Chadwick

(c) both

(d) none

 

Question 4:

Nuclides with same neutron number N but different atomic number Z is known as __________.

(a) isotopes

(b) isobars

(c) isotones

(d) none

 

Question 5:

The commonly used moderator in nuclear reactor is __________.

(a) graphite

(b) water

(c) D2O

(d) all of these

 

Question 6:

Define the term ‘activity’ of a radionuclide. Write its SI unit.

 

Question 7:

Heavy water is often used as a moderator in thermal nuclear reactors? Give reason.

 

Question 8:

Why is the ionizing power of α- particle greater than that of gamma rays?

 

Question 9:

The radioactive isotope D decays according to the sequence.

If the mass number and atomic number of D2 are 176 and 71 respectively, what is (i)the mass number (ii)atomic number of D?

                       

Question 10:

Why is a neutron most effective as a bullet in nuclear reaction?

 

Question 11:

What is the activity of one gram of 22688 Ra, whose half-life is 1622 years?

 

Question 12:

Draw a graph showing the variation of decay rate with a number of active nuclei.

 

Question 13:

If both the number of neutrons and the number of protons is conserved in each nuclear reaction, in what way is mass converted into energy (or vice versa) in a nuclear reaction? Explain.

 

Question 14:

Two radioactive samples, X, Y have the same number of atoms at t = 0. Their half-lives are 3 h and 4 h respectively. Compare the rates of disintegration of the two nuclei after 12 hours.

 

Question 15:

Why is the energy of the beta particles emitted during beta decay continuous?

 

Question 16:

A nucleus with A= 235 splits into two new nuclei whose mass number are in the ratio of 2:1. Find the radii of the new nuclei. (Consider the value of R0= 1.4 fm)

Question 17:

You are given two nuclei 73X and 43Y. Explain giving reasons, as to which one of the two nuclei is likely to be more stable?

 

Question 18:

Distinguish between Nuclear fission and nuclear fusion.

 

Question 19:

The half-life of 23892 U against α-decay is 4.5 × 109 years. Calculate the activity of 1g sample of 23892U.

 

Question 20:

A general impression exist that mass-energy interconversion takes place only in nuclear reaction and never in chemical reaction. This is strictly speaking, incorrect. Explain.

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