Dual Nature Of Light Question 411
Question: To decrease the cut-off wavelength of continuous X-rays by 25%, the potential difference across X-ray tube
Options:
A) must be increased by $ \frac{100}{3}% $
B) must be decreased by $ \frac{100}{3}% $
C) must increased by 25%
D) must decreased by 25%.
Show Answer
Answer:
Correct Answer: A
Solution:
[a] $ {\lambda_{1}}=\frac{hc}{ev_{1}};{\lambda_{2}}=\frac{hc}{ev_{2}}\Rightarrow \frac{{\lambda_{2}}}{{\lambda_{1}}}=\frac{v_{1}}{v_{2}} $
$ \Rightarrow \frac{3}{4}=\frac{v_{1}}{v_{2}}\Rightarrow ( \frac{v_{2}-v_{1}}{v_{1}} )\times 100=\frac{100}{3} $ Hence, P.D. must be increased by $ \frac{100}{3}%. $
BETA
