For a convex lens,the value of magnification m is :

1. positive
2. negative
3. both positive as well as negative
4. none

If the magnification produced by a lens is -0.5, the correct statement is:

1. the lens is concave
2. the image is virtual
3. the image is magnified
4. the image is real and diminished formed by a convex lens

If a lens deviates a ray towards its centre, its power is …………… and if it deviates the ray away from its centre, its power is ……………

1. positive, positive
2. negative, negative
3. negative, positive
4. positive, negative

On reducing the focal length of a lens, its power :

1. decreases
2. increases
3. does not change
4. first increases then decreases.