Question

Calculate the difference in energy (in joules) between a photon with

λ

= 719 nm and a photon with

λ

= 339 nm. Enter your answer in scientific notation.

Answer 1

i) Energy of photon with = 719 nm

Energy of photon is calculated by the following formula

E = hc/

where,

h = planck constant , 6.626×10^-34 J.s

c = speed of light , 2.998 ×10⁸m /s

= wavelength of photon , 719nm = 719×10^-9 m

ii) Energy of 719nm photon

E=(6.626×10^-34J.s × 2.998×10⁸m/s)/719×10^-9m = 2.76×10^-19J

iii) Energy of 339nm photon

E = ( 6.626×10^-34J.s × 2.998×10⁸m/s)/339×10^-9m = 5.86×10^-19J

iv) difference in energy = 5.86×10^-19J - 2.76×10^-19J = 3.10×10^-19 J