Question

The momentum of a radiation photon is $3.3\times {10}^{-23}$ kgm/sec. The frequency of radiation is

• A. $5\times {10}^6$Hz
• B. $4.5\times {10}^{31}$Hz
• C. $4.5\times {10}^{21}$Hz
• D. $1.49\times {10}^{19}$Hz

Answer 1

Answer: (D)

$1.49\times {10}^{19}$Hz

$\begin{array}{c}\text{Given,}\\ \text{momentum of photon}=3.3\times {10}^{-23}kgm/sec\\ \text{from de broglie Equation}\end{array}$

$\lambda =\frac{h}{p}$

$\text{and}c=f\times \lambda$

$\begin{array}{cc}\frac{c}{f}& =\frac{h}{p}\\ f& =\frac{pc}{h}\\ & =\frac{3.3\times {10}^{-23}\times 3\times {10}^8}{6.626\times {10}^{-34}}\\ f& =1.49\times {10}^{19}Hz\end{array}$