# Group Displacement Law Worksheet

Group displacement law, series, units, number of $\alpha, \beta$

Group displacement law states that on the emission of an alpha-particle the new element lies two columns left in the periodic table and mass number decreases by 4 units, and on the emission of a beta-particle the new element lies one column right in the periodic table and mass number remains the same.

Some of the important questions and answers related to group displacement law are listed below:-

Worksheet Questions:-

1. Which is not correct about group displacement law:

(a)    Emission of one particle of one type occurs at a time.

(b)   Emission of $\gamma$-particle changes mass and atomic number by one unit.

(c)    After the emission of a $\beta$-particle the mass number of newly formed species is not changed.

(d)   All are correct

2. $^{238}_{92}U \overset{-\alpha}{\rightarrow} A \overset{-\beta}{\rightarrow} C^?$. Here ‘C’ is:

(a)  $_92U^{235}$

(b) $_92U^{238}$

(c) $_{92}U^{234}$

(d) $\text{any of these}$

3. In 4n + 2 series the number of $\alpha, \beta$-particles will be respectively?

(a)    6, 4

(b)   8, 5

(c)    8, 6

(d)   7, 4

4. The units of radio activity are:

(a)    Becqueral

(b)   Rutherford

(c)    Curie

(d)   All of these

(a)    Wilson cloud chamber method’

(b)   Geiger .M.  counter method

(c)    Scintillation

(d)   All of these

6. $_{92}U^{235} \overset{\-alpha}{\underset{-\beta}{\rightarrow}} _{82}Pb^{207}$

Here the no. of $\alpha, \beta$-particles will be respectively?

(a)    7, 4

(b)   6, 4

(c)    7, 5

(d)   8, 6