Question

In YDSE, two slits have width in ratio $1:36$, then ratio of maximum intensity to minimum intensity on screen is

• A. $\frac{49}{25}$
• B. $\frac{7}{5}$
• C. $\frac{7}{6}$
• D. $\sqrt{\frac{7}{5}}$

Answer 1

The correct option is A $\frac{49}{25}$

We know that in YDSE, the slit width is directly proportional to intensity.
$\therefore \frac{I_1}{I_2}=\frac{1}{36}$

$I_2=36I_1$
$\frac{I_{max}}{I_{min}}=\frac{{({\sqrt{I}}_1+{\sqrt{I}}_2)}^2}{{({\sqrt{I}}_1-{\sqrt{I}}_2)}^2}=\frac{{({\sqrt{I}}_1+6{\sqrt{I}}_1)}^2}{{({\sqrt{I}}_1-6{\sqrt{I}}_1)}^2}$
$\frac{I_{max}}{I_{min}}=\frac{49}{25}$