Question

a) We produce a diffraction pattern on a viewing screen by means of a long narrow slit illuminated by blue light. Does the pattern expand away from the bright center (the maxima and minima shift away from the center) or contract toward it if we I. switch to yellow light or II. Decrease the slit width? 02 x 02 = 04 Marks

Answer 1

I. The angle θ increases, and the pattern expands away from the bright center

II. The angle θ increases, and the pattern expands away from the bright center

Step-by-step explanation:

The given information are;

The light used to produce a diffraction pattern = Blue light

The formula for refraction is given as follows;

d × sin(θ) = n·λ

Where;

d = The inter slit distance

θ = The angle to the maxima

n = Number to the integer next fringe

λ = Light wavelength

The wavelength of blue light is between 450 and 495 nanometers

Therefore;

I. When we switch to yellow light

The wavelength of yellow light is between 590 and 560 nanometers, which is an increase in wavelength, given that d, the inter slit distance is held constant, the angle θ increases, and the pattern expands away from the bright center

II. Decrease the slit width

When the slit width is decreased, and the wavelength remains the same, the angle θ increases, and the pattern expands away from the bright center.