Question

A beam of light travels from air into a medium. Its speed and wavelength in the medium are 1.5 × 10⁸ ms^-1 and 230 nm respectively. The wavelength of light in the air will be ______.

विकल्प

• 230 nm

• 345 nm

• 460 nm

• 690 nm

Answer 1

A beam of light travels from air into a medium. Its speed and wavelength in the medium are 1.5 × 10⁸ ms^-1 and 230 nm respectively. The wavelength of light in the air will be 460 nm.

Explanation:

We know that,

Speed = Wavelength × Wave frequency

In this equation, the wavelength is measured in meters, and frequency is measured in hertz (Hz), or the number of waves per second.

Given: v₂ (speed of medium) = `1.5 xx 10^8`, Wavelength (λ₂) = 230 nm, speed of light in air (v₁) = `3 xx 10^8` m/s

To find: Wavelength of air(λ₁)

∴ `v_1/lambda_1 = v_2/lambda_2`

`3 xx 10^8 xx 230 = 1.5 xx 10^8 xx lambda_1`

`lambda_1 = 460` nm