A monochromatic light of frequency \(500~\text{THz}\) is incident on the slits of Young's double slit experiment. If the distance between the slits is \(0.2~\text{mm}\) and the screen is placed at a distance \(1~\text{m}\) from the slits, the width of \(10\) fringes will be:
| 1. | \(1.5~\text{mm}\) | 2. | \(15~\text{mm}\) |
| 3. | \(30~\text{mm}\) | 4. | \(3~\text{mm}\) |
| Assertion (A): | If the phase difference between the light waves emerging from the slits of Young's experiment is \(\pi\) radian, the central fringe will be dark. |
| Reason (R): | Phase difference is equal to \((2\pi/\lambda)\) times of path difference. |
| 1. | Both (A) and (R) are True and (R) is the correct explanation of (A). |
| 2. | Both (A) and (R) are True but (R) is not the correct explanation of (A). |
| 3. | (A) is True but (R) is False. |
| 4. | Both (A) and (R) are False. |
| 1. | the fringes will disappear (uniform illumination). |
| 2. | screen will become dark. |
| 3. | the contrast between fringes will increase. |
| 4. | the contrast between fringes will decrease. |
| 1. | \(25\%\) | 2. | \(75\%\) |
| 3. | \(50\%\) | 4. | \(30\%\) |