Q. No.1. \(-3\hat i+4\hat j+2\hat k\)
2. \(3\hat i-4\hat j-2\hat k\)
3. \(-3\hat i-4\hat j+2\hat k\)
4. \(-3\hat i+4\hat j-2\hat k\)
1. \(45^\circ\)
2. \(30^\circ\)
3. \(55^\circ\)
4. \(50^\circ\)
A rod of length \(10~\text{cm}\) lies along the principal axis of a concave mirror of focal length \(10~\text{cm}\) in such a way that its end closer to the pole is \(20~\text{cm}\) away from the mirror. The length of the image is:
1. \(15~\text{cm}\)
2. \(2.5~\text{cm}\)
3. \(5~\text{cm}\)
4. \(10~\text{cm}\)
An object is placed at a distance of \(40\) cm from a concave mirror of a focal length of \(15\) cm. If the object is displaced through a distance of \(20\) cm towards the mirror, the displacement of the image will be:
| 1. | \(30\) cm away from the mirror |
| 2. | \(36\) cm away from the mirror |
| 3. | \(30\) cm towards the mirror |
| 4. | \(36\) cm towards the mirror |
Suppose that the lower half of the concave mirror’s reflecting surface in the given figure is covered with an opaque (non-reflective) material. What effect will this have on the image of an object placed in front of the mirror?
| 1. | the image will show only half of the object |
| 2. | the image will show the whole of the object |
| 3. | the intensity of the image will be low |
| 4. | both (2) and (3) |
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
1. \((\mu-1)t\)
2. \(2(\mu-1)t\)
3. \(\mu t\)
4. \(2\mu t\)
Then:
| 1. | \(\mu_{2}=\frac{1}{3},~\mu_{3}=\frac{1}{2}\) | 2. | \(\mu_{2}=3,~\mu_{3}=\frac{3}{2}\) |
| 3. | \(\mu_{2}=\frac{1}{3},~\mu_{3}=\frac{2}{3}\) | 4. | \(\mu_{2}=3,~\mu_{3}=2\) |
| 1. | the scattering of light. |
| 2. | the polarisation of light. |
| 3. | the colour of the sun. |
| 4. | the colour of the sky. |
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