Question

The velocity of light is 3 $\times$ 10${}^8$ m/sec. Which value is closest to the wavelength in nanometer of a quantum of light with frequency of 8$\times$ 10${}^{15}$ sec${}^{-1}$?

• A. 5.4 $\times$ 10${}^{-18}$
• B. 37.5
• C. 2.3 $\times$ 10${}^7$
• D. 1.2 $\times$ 10${}^{-2}$

Answer 1

Answer: (B)

37.5

$c=n\lambda$
$\lambda =\frac{c}{n}=\frac{3\times {10}^8}{8\times {10}^{15}}=37.5nm$