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
An object is at a distance of 30 cm in front of a concave mirror of focal length 10 cm. The image of the object will be:
1. | smaller in size. |
2. | inverted. |
3. | between the focus and centre of curvature. |
4. | All of the above. |
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 4.5 cm needle is placed 12 cm away from a convex mirror of focal length 15 cm. What is the magnification?
1. 0.5
2. 0.56
3. 0.45
4. 0.15
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 convex mirror of focal length f forms an image which is \(1 \over n\) times the length of the object. The distance of the object from the mirror is:
1. (n-1)f
2. \(({n-1 \over n})f\)
3. \(({n+1 \over n})f\)
4. (n+1)f
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.
3. 2f
4.
A rod of length 10 cm lies along the principal axis of a concave mirror of focal length 10 cm in such a way that its end closer to the pole is 20 cm away from the mirror. The length of the image is:
1. | 10 cm | 2. | 15 cm |
3. | 2.5 cm | 4. | 5 cm |
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 focal length of the mirror]
1. Zero
2.
3. f
4. 2f