Q14 of 123 Page 410

An air bubble is formed inside water. Does it act as a converging lens or a diverging lens?

The lensmaker’s formula is


Now, refractive index of water is more than air. So, hence, f<0.


And, we know, focal length is negative for a concave lens only. So, it is diverging one.


More from this chapter

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12

A thin converging lens is formed with one surface convex and the other plane. Does the position of image depend on whether the convex surface or the plane surface faces the object?

 13

A single lens is mounted in a tube. A parallel beam enters the tube and emerges out of the tube as a divergent beam. Can you say with certainty that there is a diverging lens in the tube?

 15

Two converging lenses of unequal focal lengths can be used to reduce the aperture of a parallel beam of light without losing the energy of the light. This increase the intensity. Describe how the converging lenses should be placed to do this.

 16

If a spherical mirror is dipped in water, does its focal length change?