Question

What is the effect on the interference pattern produced by a griting if the number of slits per unit length is increased? Motivate your answer.

Answer 1

Explanation:

The equation of grating is given by :

$(a+b)\ sin\theta=n\lambda$

Here,

(a+b) is called grating element

N is the number of slits per unit length, $N=\dfrac{1}{(a+b)}$

n is the order

$\lambda$ is the wavelength of light used

$\theta$ is the diffraction angle

Here, we need to write the effect on the interference pattern produced by a grating if the number of slits per unit length is increased. If the number of slits per unit length increases, the grating element decreases such that the angle of diffraction increases. Hence, the interference pattern shrinks.