A tall man, of height 6 feet, wants to see his full image. The required minimum length of the mirror will be:
1. 12 feet
2. 3 feet
3. 6 feet
4. Any length
Choose the correct mirror image of the figure:
1. | 2. | ||
3. | 4. |
Two plane mirrors, A and B are aligned parallel to each other, as shown in the figure. A light ray is incident at an angle of $30\xb0$ at a point just inside one end of A. The plane of incidence coincides with the plane of the figure. The maximum number of times the ray undergoes reflections (excluding the first one) before it emerges out is:
1. 28
2. 30
3. 32
4. 34
An object is placed 20 cm in front of a concave mirror of a radius of curvature 10 cm. The position of the image from the pole of the mirror is:
1. 7.67 cm
2. 6.67 cm
3. 8.67 cm
4. 9.67 cm
Match the corresponding entries of Column-1 with Column-2.
(Where m is the magnification produced by the mirror)
Column-1 | Column-2 |
A. m = -2 | I. convex mirror |
B. m = -1/2 | II. concave mirror |
C. m = +2 | III. real Image |
D. m = +1/2 | IV. virtual Image |
A | B | C | D | |
1. | I & III | I & IV | I & II | III & IV |
2. | I & IV | II & III | II & IV | II & III |
3. | III & IV | II & IV | II & III | I & IV |
4. | II & III | II & III | II & IV | I & IV |
When a concave mirror of focal length f is immersed in water, its focal length becomes f', then:
1. | f'=f |
2. | f'<f |
3. | f'>f |
4. | The information is insufficient to predict |
A concave mirror gives an image three times as large as the object placed at a distance of 20 cm from it. For the image to be real, the focal length should be:
1. 10 cm
2. 15 cm
3. 20 cm
4. 30 cm
A thin rod of length f/3 lies along the axis of a concave mirror of focal length f. One end of its magnified, real image touches an end of the rod. The length of the image is:
1. f
2. $\frac{1}{2}f$
3. 2f
4. $\frac{1}{4}f$
The distance between the object and its real image formed by a concave mirror is minimum when the distance of the object from the centre of curvature of the mirror is: [f $\to $ focal length of the mirror]
1. Zero
2. $\frac{\mathrm{f}}{2}$
3. f
4. 2f
When a ray of light falls on a given plate at an angle of incidence $60\xb0$, the reflected and refracted rays are found to be normal to each other. The refractive index of the material of the plate is:
1. $\frac{\sqrt{3}}{2}$
2. 1.5
3. 1.732
4. 2