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. | \(m= -\frac{1}{2}\) | II. | concave mirror |
C. | \(m= +2\) | III. | real Image |
D. | \(m= +\frac{1}{2}\) | 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 \(\frac{f}{3}\) 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. \(\frac{f}{2}\)
3. \(2f\)
4. \(\frac{f}{4}\)
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