Question

The legs of a spherometer are 5 cm apart. There are 10 division cm^–1 on linear scale and circular scale has 100 divisions. The height h of a convex mirror measured in 2 MSD + 37 circular scale divisions. Find radius of curvature of convex mirror.

• A. 20.003 cm
• B. 18.408 cm
• C. 17.399
• D. 17.983 cm

Answer 1

Answer: (B)

18.408 cm

Answer 2

Least count = $\frac { 1 / 10 } { 100 }$ = 10^–3 cm

h = 2 × (0.1) + 37 (10^–3) = 0.237 cm

R = $\frac { l ^ { 2 } } { 6 \mathrm {~h} }$ +=$\frac { 25 } { 1.362 }$+ 0.118 = 18.408 cm