1. | infinity | 2. | \(+2~\text{D}\) |
3. | \(+20 ~\text{D}\) | 4. | \(+5~\text{D}\) |
1. | \(120^\circ\) | 2. | \(30^\circ\) |
3. | \(60^\circ\) | 4. | \(90^\circ\) |
A concave lens of focal length \(-25\) cm is sandwiched between two convex lenses, each of focal length, \(40\) cm. The power in dioptre of the combined lens would be:
1. | \(55\) | 2. | \(9\) |
3. | \(1\) | 4. | \(0.01\) |
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. | \(-3\hat i+4\hat j+2\hat k\) | 2. | \(3\hat i-4\hat j-2\hat k\) |
3. | \(-3\hat i-4\hat j+2\hat k\) | 4. | \(-3\hat i+4\hat j-2\hat k\) |