Question

if a diffraction grating produces a third-order bright spot for red light (of wavelength 650 nm ) at 68.0 ∘ from the central maximum, at what angle will the second-order bright spot be for violet light (of wavelength 450 nm )?

Answer 1

Answer:

The angle is 25.34°.

Explanation:

Given that,

Wave length = 650 nm

Angle = 68.0°

We need to calculate the distance

For a diffraction grating

$d\sin\theta=m\lambda$

$d=\dfrac{2\times650\times10^{-9}}{\sin68.0}$

$d=2.10\times10^{-6}\ m$

We need to calculate the angle

Using formula for angle

$d\sin\theta=m\lambda$

$\sin\theta=\dfrac{m\times\lambda}{d}$

$\sin\theta=\dfrac{2\times450\times10^{-9}}{2.10\times10^{-6}}$

$\sin\theta=25.34^{\circ}$

Hence, The angle is 25.34°.