Question

In a simple slit diffraction pattern intensity and width of fringes are

• A. Unequal width
• B. Equal width
• C. Equal width and equal intensity
• D. Unequal width and unequal intensity

Answer 1

The correct option is B Equal width

For a single slit diffraction pattern, the $n^{th}$ order minima is given by $asin\theta =n\lambda$

$⟹a\frac{y}{D}=n\lambda$

Thus distance between two consecutive minima is $y_{n+1}-y_n$

$=\frac{D\lambda }{a}\left(\right(n+1)-n)=\frac{D\lambda }{a}$

However the intensity decreases as the order of fringe increases.

Hence the width of fringe is constant.

Correct answer is option B.