### NEET Physics - New - Ray Optics and Optical Instrument

#### Question - 1

A ray of light is successively deflected from two plane mirrors inclined to each other at a certain angle. If the total deviation in the path of the rays reflected from the two mirrors be ${ 300 }^{ 0 }$ , then what is the number of images formed ?

• A 30
• B 15
• C 11
• D 5

#### Question - 2

A Concave mirror form the real image of an object which is magnified 4 times. The object is moved 3 cm away, the magnification of the image is 3 times. What is the focal length of the mirror?

• A 3 cm
• B 12 cm
• C 36 cm

#### Question - 3

A room (cubical) is made of mirrors. An insect is moving along the diagonal on the floor , such that the velocity of image of insect on two adjacent wall mirrors, is ${ 10cms }^{ -1 }$. The velocity of image of insect in ceiling mirror is

• A ${ 10cms }^{ -1 }$
• B ${ 20cms }^{ -1 }$
• C $\frac { 10 }{ \sqrt { 2 } } cm{ s }^{ -1 }$
• D $10\sqrt { 2 } cm{ s }^{ -1 }$

#### Question - 4

The image formed by a convex mirror of focal length 30 cm is a quarter of the size of the object.The distance of the object from the mirror is

• A 30 cm
• B 90 cm
• C 120 cm
• D 60 cm

#### Question - 5

A Convex lens and a concave lens, each having same focal length of 25 cm, are put in contact to form a combination of lenses. The power in dioptres of the combination is

• A 25
• B 50
• C infinite
• D zero

#### Question - 6

In the given figure, the angle of reflection is

• A ${ 30 }^{ 0 }$
• B ${ 60 }^{ 0 }$
• C ${ 45 }^{ 0 }$
• D None of these

#### Question - 7

Aglass slab ( $\mu$ = 1.5) of thickness 6 cm is placed over a paper. What is the shift in the letters?

• A 4 cm
• B 2 cm
• C 1 cm
• D None of these

#### Question - 8

A 4 cm thick layer of water covers a 6 cm thick glass slab. Acoin placed at the bottom of the slab and is being observed from the air side along the normal to the surface. Find the apprent position of the coin from

• A 7.0 cm
• B 8.0 cm
• C 10 cm
• D 5 cm

#### Question - 9

A microscope is focussed on a mark on a piece of paper and then, a slab of glass of thickness 3 cm and refractive index 1.5 is placed over the mark. How should the microscope be moved to get the mark in focus again?

• A 1 cm upward
• B 4.5 cm downward
• C 1 cm downward
• D 2 cm upward

#### Question - 10

A small coin is resting on the bottom of a beaker filled with a liquid . A ray of light from the coin travels up to the surface of the liquid and moves along its surface as shown in figure. How fast is the light travelling in the liquid?

• A $1.8\times { 10 }^{ 8 }m{ s }^{ -1 }$
• B $2.4\times { 10 }^{ 8 }m{ s }^{ -1 }$
• C $3.0\times { 10 }^{ 8 }m{ s }^{ -1 }$
• D $1.2\times { 10 }^{ 4 }m{ s }^{ -1 }$