Dual Nature Of Light Question 76
Question: An electron initially at rest, is accelerated through a potential difference of 200 volt, so that it acquires a velocity $ 8.4\times 10^{6}m/s. $ The value of e/m of electron will be [DPMT 2003]
Options:
A) $ 2.76\times 10^{12}C/kg $
B) $ 1.76\times 10^{11}C/kg $
C) $ 0.76\times 10^{12}C/kg $
D) None of these
Show Answer
Answer:
Correct Answer: B
Solution:
$ \frac{1}{2}mv^{2}=eV\Rightarrow \frac{e}{m}=\frac{v^{2}}{2V}=\frac{{{(8.4\times 10^{6})}^{2}}}{2\times 200} $ $ =1.76\times 10^{11},\frac{C}{kg}. $
BETA
