Two regions of a soap film ( ) have thicknesses of and

PHYSICS · Subjective · A Level · Physics · Waves · Waves

Problem

Two regions of a soap film (

n=1.33

) have thicknesses of

250\,\text{nm}

and

400\,\text{nm}

. When illuminated by white light at normal incidence, which region will reflect blue light of wavelength

470\,\text{nm}

in air more strongly? State the chosen thickness.