Inside water, an air bubble behaves

Important Questions on Refraction at Spherical Surfaces and Spherical Lens

MEDIUM

12th West Bengal Board

IMPORTANT

A Text Book of PHYSICS PART 2 : CLASS 12>Chapter 14 - Refraction at Spherical Surfaces and Spherical Lens>EXERCISE 14>Q 26

An air bubble inside a glass slab $(\mathrm{\mu }=1.5)$ appears at $6 \mathrm{cm}$ when viewed from one side and $4 \mathrm{cm}$ when viewed from the opposite side. The thickness of the slab is

EASY

12th West Bengal Board

IMPORTANT

A Text Book of PHYSICS PART 2 : CLASS 12>Chapter 14 - Refraction at Spherical Surfaces and Spherical Lens>EXERCISE 14>Q 27

A thin glass $(\mathrm{\mu }=1.5)$ lens has optical power of $-5\mathrm{D}$ in air. Its optical power in a liquid medium with $\mathrm{\mu }=1.6$ will be

EASY

12th West Bengal Board

IMPORTANT

A Text Book of PHYSICS PART 2 : CLASS 12>Chapter 14 - Refraction at Spherical Surfaces and Spherical Lens>EXERCISE 14>Q 28

When monochromatic red light is used instead of blue light is incident in a convex lens, its focal length will

HARD

12th West Bengal Board

IMPORTANT

A Text Book of PHYSICS PART 2 : CLASS 12>Chapter 14 - Refraction at Spherical Surfaces and Spherical Lens>EXERCISE 14>Q 29

A Planoconvex convex lens has a maximum thickness of $6 \mathrm{cm}.$ When placed on a horizontal table with the curved surface in contact with the table surface, the apparent depth of the bottom-most point of the lens is found to be $4 \mathrm{cm}$. If the lens is inverted such that the plane face of the lens is in contact with the surface of the table, the apparent depth of the centre of the plane face is found to be $(17/4) \mathrm{cm}$. The radius of curvature of the lens is 

HARD

12th West Bengal Board

IMPORTANT

A Text Book of PHYSICS PART 2 : CLASS 12>Chapter 14 - Refraction at Spherical Surfaces and Spherical Lens>EXERCISE 14>Q 30

Two thin lenses have a combined power of $+9\mathrm{D}$, when they are separated by a distance of $20 \mathrm{cm}$, their equivalent power becomes $+\frac{27}{5}\mathrm{D}$,

then their individual powers are

MEDIUM

12th West Bengal Board

IMPORTANT

A Text Book of PHYSICS PART 2 : CLASS 12>Chapter 14 - Refraction at Spherical Surfaces and Spherical Lens>EXERCISE 14>Q 31

The focal length of the lens of refractive index $\left(\mu =1.5\right)$ in air is $10 \mathrm{cm}$. If air is replaced by water of $\mu =\frac{4}{3}$, its focal length is

EASY

12th West Bengal Board

IMPORTANT

A Text Book of PHYSICS PART 2 : CLASS 12>Chapter 14 - Refraction at Spherical Surfaces and Spherical Lens>EXERCISE 14>Q 32

Two thin lenses of focal length $20 \mathrm{cm}$ and $25 \mathrm{cm}$ are placed in contact. The effective power of the combination

HARD

12th West Bengal Board

IMPORTANT

A Text Book of PHYSICS PART 2 : CLASS 12>Chapter 14 - Refraction at Spherical Surfaces and Spherical Lens>EXERCISE 14>Q 33

A convex lens of focal length $30 \mathrm{cm}$ produces $5$ times magnified real image of an object. What is the object distance?