Answer:
8 m
Explanation:
u = - 4 m
height of image = half of height of object
m = height of image / height of object = 1/2
m = - v / u = 1/2
v = - u / 2 = - (-4) / 2 = 2 m
Use the mirror formula
1 / u + 1 / v = 1 / f
1 / (-4) + 1 / 2 = 1 / f
1 / f = 1 /2 - 1 / 4 = 1 / 4
f = 4 m
radius of curvature = 2 x focal length
radius of curvature = 2 x 4 = 8 m
