Question

Orange light has a wavelength of $6\times {10}^{-7}m$. What is its frequency? The speed of light is $3\times {10}^{8}m/s$.

• A. $2\times {10}^{15}Hz$
• B. $2\times {10}^{-15}Hz$
• C. $5\times {10}^{14}Hz$
• D. $5\times {10}^{-14}Hz$
• E. $2\times {10}^{14}Hz$

Answer 1

Answer: (C)

$5\times {10}^{14}Hz$

The relation between frequency and wavelength is $v=f\lambda$

Here, $v=c=3\times {10}^{8}m/s$ , speed of light and wavelength $\lambda =6\times {10}^{-7}m$

Thus, frequency $f=\frac{c}{\lambda }=\frac{3\times {10}^8}{6\times {10}^{-7}}=5\times {10}^{14}$ Hz