Answer:
44.4cm
Step-by-step explanation:
glass has an index of refraction .n = 1.54
radii of curvature of 40 cm R1 = 40 by
radii of curvature of 600 cm R2 = 60
Now, by lens maker formula
1/f = (n - 1) (1/R1 - 1/R2)
Putting in the given values for n = 1.54 , we get f = 22.2
f = 1 / 0.0225
f = 44.4cm
so, focal length in air will be = 44.4 cm