Question

Calculate the frequencies and energies for these 4 wavelengths: 410 nm, 435nm, 487nm, 655nm

Answer 1

c=λv ,

where λ is wavelength in meters

v is frequency in hertz, 1/s or s^-1

c=3.0 x 10⁸m/s (the speed of light in a vacuum).

Question 1

410 nm = 4.1 x10^-7m

we can rearrange the equation above and solve for frequency, since we already know the constant, c.

v =c/ λ

frequency v = 3.0 x 10⁸ / 4.1 x10^-7= 7.32 x  10¹⁴ s^-1

Energy is directly proportional to frequency. To calculate energy from frequency (or vice Versa), use the following equation

E=hv

where E is Energy in Joules (J)

v is frequency in hertz, 1/s or s^-1

h=6.626 x 10^-34 J s

E=hn

E=(6.626 x 10^-34Js)(7.32 x 10¹⁴ s^-1)

E= 4.848 x 10^-19J

Question 2

435nm

If we perform as mentioned earlier

frequency v = = 6.89 x  10¹⁴ s^-1

E= 4.565 x 10^-19J

Question 3

487nm

If we perform as mentioned earlier

frequency v = = 6.16 x  10¹⁴ s^-1

E= 4.08x 10^-19J

Question 4

655nm

If we perform as mentioned earlier

frequency v = = 4.57 x  10¹⁴ s^-1

E= 3.028 x 10^-19J