Question

liggt source on the screen direct or inverse​

Answer 1

Answer:

When the mirror is present:

Intensity of light at screen due to direct wave from point source

I

1

=K/a

2

Intensity of light at screen due to reflected wave from mirror

I

2

=K/(3a)

2

=K/9a

2

(as this wave covers a total distance of 3a)

Now as the two waves are independent to each other, therefore total intensity at the screen:

I=I

1

+I

2

=K/a

2

+K/9a

2

,

I=10K/9a

2

.......................eq1

When the mirror is removed:

Intensity of light at screen due to direct wave from point source

I

′

=K/a

2

.........................eq2

Dividing eq2 by eq1:

I

′

/I=9/10

I

′

=9I/10