Where should an object be placed so that a real and inverted image of same size is obtained by a convex lens

(a)

f

(b)

2f

(c)

infinity

(d)

between f and 2f

Magnification of a convex lens is

(a)

Positive

(b)

negative

(c)

either positive or negative

(d)

zero

Power of a lens is –4D, then its focal length is

(a)

4m

(b)

–40m

(c)

–0.25 m

(d)

–2.5 m

The eye defect ‘presbyopia’ can be corrected by

(a)

convex lens

(b)

concave lens

(c)

convex mirror

(d)

Bi focal lenses

If V_B, V_G, V_R be the velocity of blue, green and red light respectively in a glass prism, then which of the following statement gives the correct relation?

(a)

V_B = V_G = V_R

(b)

V_B > V_G >V_R

(c)

V_B < V_G < V_R

(d)

V_B < V_G > V_R