Advertisements
Advertisements
प्रश्न
A double convex lens of glass has both faces of the same radius of curvature 17 cm. Find its focal length if it is immersed in water. The refractive indices of glass and water are 1.5 and 1.33 respectively.
संख्यात्मक
Advertisements
उत्तर
Lens makes a formula for a double convex lens:
`1/f = (n_g/n_w - 1)(1/R_1 - 1/R_2)`
n = `n_g/n_w`
= `1.5/1.33`
= 1.127
`1/f = (1.127 - 1)(1/17 - 1/-17)`
= `0.127 xx 2/17`
= `0.254/17`
`1/f` = 0.01494
f = `1/0.01494`
= 66.93 cm
f = 67 cm
shaalaa.com
या प्रश्नात किंवा उत्तरात काही त्रुटी आहे का?
