A radioactive source emits X–rays of very short wavelength (10\(^{-13}\)m ). What is the frequency of these rays?
- 2 × 1018HZ
- 3 × 10 19HZ
-
3 × 1021HZ
- 3 × 10-19HZ
The correct answer is: C
Explanation
\(Wavelength (\lambda) = 10^{-13}m\)
Speed of X-ray = speed of light \(C = 3×10^{8}m/s\)
Frequently (f) = ?
\(Using V = f\lambda (or (– f π for electromagnetic wave)\)
\(f = \frac{c}{\lambda} = 3 \times 10^{8} ÷ 10^{-13} = 3 \times 10^{8} \times 10^{13}\)
= \(3 \times 10^{8} \times 10^{13}\)
= \(3 \times 10^{21}Hz\)
There is an explanation video available .