A mirror is formed by cutting part of sphere .The sphere has a radius of 10 cm if the volume of Sphere is made 27 times what will be the new focal length of the mirror formed
Answers
Answered by
3
Given : A mirror is formed by cutting a part of sphere. The sphere has a radius of 10cm .
now the volume of sphere is made 27 times of its initial.
To find : The new focal length of the mirror formed.
solution : when radius of sphere is 10cm.
focal length of mirror would be , f = r/2 = 5 cm
now volume of sphere is made of 27times.
i.e., volume of new sphere = 27 × volume of sphere initially
⇒4/3 πR³ = 27 × 4/3 π (10cm)³
⇒R³ = (3)³ × (10cm)³ = (30cm)³
⇒R = 30cm
so new focal length of the mirror formed, f' = R/2 = 30/2 = 15cm
Therefore the new focal length of the mirror formed is 15 cm
Answered by
0
Answer:
The radius of curvature of the mirror =24cm.
Thus the focal length
=24cm/2
=12cm.
Explanation:
Similar questions