Question

Which of the following changes would increase the seperation between the bright fringes in the diffraction pattern formed by diffraction grating?
A. INCREASE THE WAVELENGTH OF THE LIGHT

B. IMMERSE THE APPARATUSE IN WATER

C. INCREASE THE SEPERATION BETWEEN THE SLITS

D. NONE OF THESE

E. MORE THAN ONE OF THESE

Answer 1

Answer: Option (A) is the correct answer.

Explanation:

One of the equation for diffraction grating is as follows.

             $dsin \theta = m \lambda$

or,       $sin \theta = \frac{m \lambda}{d}$

And, for greater value of $Sin \theta$ the spacing gets wider.

Hence, in order to increase $Sin \theta$, the wavelength would have to increase or spacing has to decrease.

Thus, we can conclude that increase the wavelength of the light changes would increase the separation between the bright fringes in the diffraction pattern formed by diffraction grating.