Question

Intensity at center in YDSE is $I_0$. If one slit is covered, then intensity at center will be:

• A. $I_0$
• B. $2I_0$
• C. $I_0/4$
• D. $I_0/2$

Answer 1

The correct option is C $I_0/4$

As intensity is directly proportional to the square of amplitude. If amplitude of wave of each source is a then intensity will become ${\left(2a\right)}^2=4a^2$. If one source is closed, then new intensity is $I^{{}^{\prime }}$given by :

$I_0=4I^{{}^{\prime }}$

$I^{\prime }=\frac{I_0}{4}$