Modern Physics Ques 174
- To produce characteristic $X$-rays using a tungsten target in an $X$-ray generator, the accelerating voltage should be greater than …… V and the energy of the characteristic radiation is …… eV. (The binding energy of the innermost electron in tungsten is $40$ $ keV$ ).
(1983, 2M)
Show Answer
Answer:
Correct Answer: 174.$(30 \times 10^{3} , 30 \times 10^{3} )$
Solution:
- Minimum voltage required is corresponding to $n=1$ to $n=2$.
Binding energy of the innermost electron is given as $40$ $ keV$ i.e. ionisation potential is $40 $ $kV$. Therefore,
$ V _{\min }=\frac{40 \times 10^{3} (\frac{1}{1^{2}}-\frac{1}{2^{2}})}{(\frac{1}{1^{2}}-\frac{1}{\infty})}=30 \times 10^{3} V $
The energy of the characteristic radiation will be $30 \times 10^{3} $ $eV$.
BETA
