Question

The refractive index and radius of curvatures of lens are given as 1.5, 30 cm and -35 cm respectively. find the focal length of the lens. (hint: lensmaker's equation)

Answer 1

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Given,

• Radius of curvatures of lens are 1.5 ,30 cm and -35 cm

To Find:-

• Find the focal length of the lens.

Calculations:-

• (n-1)(1/R1 - 1/R2)--> Lens makers formula.

according to the question,

The given values are.

n=1.5

R1 = 30

R2 = -35

=(1.5-1)(1/30-1/-35)

= (0.5)(1/30 - 1/-35)

using the formula 1/f

= 1/12

f = 12 cm

Thus ,the focal length of the lens is 12cm.

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-Happies!!