Q. Calculate the energy in joule corresponding to light of wavelength 45 nm : (Planck's constant h = $6.63 \times 10^{-34}$ Js; speed of light c = $3 \times 10^8$ $ms^{-1}$)
A) $6.67 \times 10^{15}$
B) $6.67 \times 10^{11}$
C) $4.42 \times 10^{-15}$
D) $4.42 \times 10^{-18}$
Explanation
[Solution] $E = \frac{hc}{\lambda} = \frac{6.63\times10^{-34} \times 3\times10^8}{45\times10^{-9}} = 4.42 \times 10^{-18}$ J. (The key in the PDF leaves this question blank.) Answer (4).
Reviewed by Dr. Abubacker
Physics Educator & NEET/JEE Specialist
Ph.D. in Physics with 19+ years of teaching experience.