In interference pattern by two identical slits the intensity of central maximum is I. what will be the intensity at the same spot if one of the slits is closed?

Explanation

Let the amplitudes of the waves be a and a.
`:. A _("max")` a+a=2a
So , `I_("max")=a_("max")^(2)=4a^(2)=4I_(0)`
[`I_(0)` = intensity due to each slit]
When one of the slits is closed the intensity at the same spot is
`I_(0)=(I_("max"))/(4)=(I)/(4).`