Question

Calculate the frequency of red light of wavelength 7000 Å. The speed of light is 3 × 10⁸ m/s.

Answer 1

Given:

Wavelength (λ) = 7000 Å = 7000 × 10⁻¹⁰ m = 7 × 10⁻⁷ m

Speed of light (c) = 3 × 10⁸ m/s

Formula:

Frequency (v) = `"Speed of light (c)"/"Wavelength (λ)"`

= `(3 xx 10^8)/(7 xx 10^-7)`

= `3/7 xx 10^15`

= 0.42857 × 10¹⁵ Hz

= 4.29 × 10¹⁴ Hz