A point source of light is placed in front of a plane mirror. Choose the correct statement
1. | All the reflected rays meet at a point when produced backward. |
2. | Only the reflected rays close to the normal meet at a point when produced backward. |
3. | Only the reflected rays making a small angle with the mirror meet at a point when produced backward. |
4. | Light of different colours make different images |
Total internal reflection can take place only if:
1. | light goes from optically rarer medium (smaller refractive index) to optically denser medium. |
2. | light goes from optically denser medium to rarer medium. |
3. | the refractive indices of the two media are close to each other. |
4. | the refractive indices of the two media are widely different. |
In image formation from spherical mirrors, only paraxial rays are considered because they
1. are easy to handle geometrically
2. contain most of the intensity of the incident light
3. form nearly a point image of a point source
4. show minimum dispersion effect
A point object is placed at a distance of 30 cm from a convex mirror of focal length 30 cm. The image will form at
1. infinity
2. pole
3. focus
4. 15 cm behind the mirror
The figure shows two rays A and B being reflected by a mirror and going as A' and B'. The mirror,
1. is plane
2. is convex
3. is concave
4. may be any spherical mirror
The image formed by a concave mirror:
1. | is always real |
2. | is always virtual |
3. | is certainly real if the object is virtual |
4. | is certainly virtual if the object is real |
The figure shows three transparent media of refractive indices \(\mu_1,~\mu_2\) and \(\mu_3\). A point object \(O\) is placed in the medium \(\mu_2\). If the entire medium on the right of the spherical surface has refractive index \(\mu_1\), the image forms at \(O'.\) If this entire medium has refractive index \(\mu_3\), the image forms at \(O''.\) In the situation shown,
1. | \(O'\) and \(O''.\) | the image forms between
2. | \(O'.\) | the image forms to the left of
3. | \(O''.\) | the image forms to the right of
4. | \(O'\) and the other at \(O''.\) | two images form, one at
Four modifications are suggested in the lens formula to include the effect of the thickness t of the lens. Which one is likely to be correct?
1. \(\frac{1}{v}-\frac{1}{u}=\frac{t}{u f}\)
2. \(\frac{t}{v^{2}}-\frac{1}{u}=\frac{1}{f}\)
3. \(\frac{1}{v-t}-\frac{1}{u+t}=\frac{1}{f}\)
4. \(\frac{1}{v}-\frac{1}{u}+\frac{t}{u v}=\frac{t}{f}\)
A double convex lens has two surfaces of equal radii \(R\) and refractive index \(m=1.5.\) We have:
1. \(f=R/2\)
2. \(f=R \)
3. \(f=-R\)
4. \(f=2R\)
A point source of light is placed at a distance of 2 f from a converging lens of focal length f. The intensity on the other side of the lens is maximum at a distance
1. f
2. between f and 2 f
3. 2 f
3. more than 2 f