1. | \(120^\circ\) | 2. | \(30^\circ\) |
3. | \(60^\circ\) | 4. | \(90^\circ\) |
A beam of light is incident vertically on a glass slab of thickness \(1\) cm, and refractive index \(1.5.\) A fraction \(A\) is reflected from the front surface while another fraction \(B\) enters the slab and emerges after reflection from the back surface. The time delay between them is:
1. | \(10^{-10}\) s | 2. | \(5\times 10^{-10}\) s |
3. | \(10^{-11}\) s | 4. | \(5\times 10^{-11}\) s |