JAMB - Physics (1992 - No. 23)
A concave mirror has a radius of curvature of 36cm. At what distance from the mirror should an object be placed to give a real image three times the size of the object?
12cm
24cm
48cm
108cm
Explication
F = \(\frac{uv}{u + v}\)
v = 3u
18 = \(\frac{3u \times u}{3u + u}\)
u = 24cm
v = 3u
18 = \(\frac{3u \times u}{3u + u}\)
u = 24cm