Question

Ultraviolet radiation has a wavelength of 300Å. If the velocity of the electromagnetic wave is 3 × 10⁸ ms^-1. Calculate:

1. frequency
2. time period.

Answer 1

Wavelength = λ = 300Å = 300 × 10^-10 m

Velocity = v = 3 × 10⁸ ms^-1 

Frequency = f = ?

Time period = T = ?

(i) We know v = λf

f = `"v"/lambda = (3 xx 10^8)/(300 xx 10^-10)`

f = `(3 xx 10^8)/(3 xx 10^-8) = 10^16` Hz

(ii) Time period = T = `1/"f"`

T = `1/10^16`

T = 10^-16 s