Diffraction - exam practice

A diffraction grating has 500 lines per mm. When monochromatic light is incident normally on the grating the third-order spectral line is formed at an angle of 60° from the normal to the grating.

What is the wavelength of the monochromatic light?

In a diffraction-grating experiment the maxima are produced on a screen.

What causes the separation of the maxima of the diffraction pattern to decrease?

White light passes through a single narrow slit and illuminates a screen.

What is observed on the screen?

When light of wavelength 5.0 × 10⁻⁷ m is incident normally on a diffraction grating the fourth-order maximum is observed at an angle of 30°.

What is the number of lines per mm on the diffraction grating?

Monochromatic light of wavelength 490 nm falls normally on a diffraction grating that has 6 x 10⁵ lines per metre. Which one of the following is correct?

A diffraction grating is illuminated normally.

The second-order maximum for light of wavelength 650 nm occurs at the same angle as the third-order maximum for light of wavelength λ.

What is λ?

A narrow beam of monochromatic light is incident normally to a diffraction grating.

The first-order diffracted beam makes an angle of 20° with the normal to the grating.

What is the highest order visible with this grating at this wavelength?

Monochromatic light is incident normally on a diffraction grating that has 4.50 × 10⁵ lines m⁻¹.

The angle between the second-order diffraction maxima is 44°.

What is the wavelength of the light?

Monochromatic electromagnetic radiation of wavelength 5.8 × 10^–7 m is incident normally on a diffraction grating with 3.0 × 10⁵ lines per metre.

What is the highest order maximum produced?