Question

The value of Planck's constant is $6.63\times {10}^{-34}js$. The velocity of light is $3.0\times {10}^{8}m{s}^{-1}$ . Which value is closest to the wavelength in nanometers of a quantum of light with frequencty of $8\times {10}^{15}{s}^{-1}$

• A. 3 × 10⁷
• B. 2 × 10^-25
• C. 5 × 10^-8
• D. 4 × 10¹

Answer 1

The correct option is D

4 × 10¹

$\lambda =\frac{c}{v}=\frac{3\times {10}^8}{8\times {10}^{15}}=3.75\times {10}^{-8}$

= $3.75\times {10}^{-8}\times {10}^{9}nm=4\times {10}^{1}nm$