How to solve
the size of the central maximum is given by 2λ/a
here "a" is the slit width.
It can be seen that if the a is doubled, size of the central maximum is halved.
but doubling the width of the slit causes a double amount of light energy to get incident on the screen as compared to that with the original width.
because of this, light energy is now confined into half of the area on the screen and the size of the central maximum is halved.
which increases the intensity by four times.
You have rated this answer /10