Question

say the answer please
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Answer 1

Explanation:

Question

• If the radius of curvature of a lens is 30 cm, then what is its focal length.

Solution

• r = 2f
• radius of curvature = 2focal length
• 30 = 2f
• f = 30/2
• f = 15

Hence, the focal length (f) is 15 cm.

Question

• In the experiment of refraction through a glass slab, the angle of incidence should be less than 90°. Why ?

Solution

Required explanation :

• In the experiment of refraction through a glass slab, the angle of incidence should be less than 90° because the light is travelling from optically rarer medium to optically denser medium, glass is optically denser medium than air and water. The lateral displacement remains the same for different angles of incidences.

Answer 2

Answer:

r = 2f

radius of curvature = 2focal length

30 = 2f

f = 30/2

Explanation:

15