Ray Optics Neet Questions

Ray Optics Neet Questions 1

      In  spherical mirrors, we consider only paraxial rays for forming the image, because :

(1) They are easy to work for geometrical purpose

(2) They consist of mostly intense incident light

(3) They form point image of the point object

(4) They produce minimum dispersion

Ans:

(3) They form point image of the point object

Ray Optics Neet Questions 2

 

      An object is placed at 30cm distance from a concave mirror of focal length 20cm then nature magnification of the image will be -

(1) Real and -2

(2)  Virtual and -2

(3) Real and +2

(4)  Virtual and +2

Ans:

(1) Real and -2

Light Question 3

     The refractive index for infrared rays:

(1) Is equal to ultraviolet rays

(2) Is equal to red colour rays

(3) Less than ultraviolet rays

(4) Greater than ultraviolet rays

Ans:

(2) Is equal to red colour rays

Light Question 4

     Total internal reflection occurs, when

(1) Light travels from optically rarer medium to optically denser medium

(2) Light travels from optically denser medium to optically rarer medium

(3) Refractive indices of both medium are equal

(4) Refractive indices of both medium are different 

Ans:

(2) Light travels from optically denser medium to optically rarer medium

Light Question 5

       When an object is placed at the distance of 20 cm from a concave lens, then small image is formed then the correct statement will be :

(1) Image will be inverted

(2) Image may be real

(3) Image is formed at 20 CM distance

(4) The focal length of the lens may be less than 20 cm

Ans:

(4) The focal length of the lens may be less than 20 cm

Light Question 6

       A convex lens of power + 6D is in contact with the concave lens of power -4D. What will be the focus length and nature of the combined lens?

(1) Concave, 25cm

(2) Convex, 50 cm

(3) Concave, 20cm

(4) Convex 100cm

Ans:

(2) Convex, 50 cm

Light Question 7

       An ray passes through on equatorial triangle in such a way that its angle of of incidence and angle of of emergence are equal and this angle is 3/4 of angle of prism. Then angle of deviation will be:

(1) `45 ^\circ`

(2) `70 ^\circ`

(3) `39 ^\circ`

(4) `30 ^\circ`

Ans:

(4) `30 ^\circ`

Light Question 8

    The image formed by objective lens of a compound microscope will be :

    

(1) Virtual and bigger

(2) Virtual and small

(3) Real and point size

(4) Real and bigger

Ans:

(4) Real and bigger

Light Question 9

    Convexo-convex lens of refractive index 1.47 is dipped in a liquid, then it behave like a simple plane sheet of glass it means, the refractive index of liquid is

(1) Greater than the refractive index of of glass

(2) Less than the refractive index of glass

(3) Equal to the refractive index of glass

(4) Less than one

Ans:

(3) Equal to the refractive index of glass

Light Question 10

       The angle of minimum deviation of a Prism will be equal to its angle of refractive index, If refractive index of prism is

(1) Between `\sqrt 2` and 2

(2) Less than 1

(3) Greater than 2

(4) Between `\sqrt 2` and 1

Ans:

(1) Between `\sqrt 2` and 2

Light Question 11

       A ray of light falling normally on a plane mirror, then angle of reflection will be :

(1) `90 ^\circ`

(2) `180 ^\circ`

(3) `0 ^\circ`

(4) `45 ^\circ`

Ans:

(3) `0 ^\circ`

Light Question 12

       A focal length of a concave mirror is 20 cm. An object is placed at a distance of 20cm in front of mirror. Its image will be formed at

(1) At 2f

(2) At f

(3) At 0

(4) At `\infty`

Ans:

(4) At `\infty`

Light Question 13

       An observer is watching the stars to be twinkle on Earth. The cause is

(1) It is true that starts do not emit light continuously

(2) Frequency absorption of light of Stars by atmosphere of their own

(3) Frequency absorption of light of Stars by atmosphere of Earth

(4) Increase and decrease of the refractive index in atmosphere of Earth

Ans:

(4) Increase and decrease of the refractive index in atmosphere of Earth

Light Question 14

       If yellow light is refracted at angle of minimum deviation from prism, then :

(1) Angle of India incidence and angle of emergence are equal

(2) The sum of the angle of incidence and angle of emergence is 90 degree

(3) Angle of incidence is less than angle of emergence

(4) Angle of incidence is greater than angle of emergence 

Ans:

(1) Angle of India incidence and angle of emergence are equal

Light Question 15

       For a healthy eye, the least distance of distinct vision and maximum distance will be:

(1) 25 cm and 100 cm

(2) 25 cm and infinite

(3) 100 cm and infinite

(4) Zero and the distance between zero to infinite

Ans:

(2) 25 cm and infinite

Light Question 16

       The length of a simple astronomical telescope is equal to:

(1) Difference between focal length of two lenses

(2) Half of the sum of focal distances

(3) Sum of the focal distance

(4) Multiplication of the focal distance

Ans:

(3) Sum of the focal distance

Light Question 17

       Virtual image of size greater than object may be formed by :

(1) Convex mirror

(2) Concave mirror

(3) Plane mirror

(4) Concave lens

Ans:

(2) Concave mirror

Light Question 18

       In compound microscope, the final image is formed:

(1) Real and erect

(2) Virtual and inverted

(3) Virtual and erect

(4) Real and inverted 

Ans:

(2) Virtual and inverted

Light Question 19

       In reflecting type telescope, the objective used is:

(1) Convex lens

(2) Convex mirror

(3) Prism

(4) Concave mirror

Ans:

(4) Concave mirror

Light Question 20

       The power of the objective lens and eyepiece of an astronomical telescope are 5D and 20D. They form image at infinity. What will be the magnifying power of telescope.

(1) 4

(2) 2

(3) 100

(4) 0.25

Ans:

(1) 4

Light Question 21

       The power of convex lens is :

(1) Negative

(2) Positive

(3) Zero

(4) Imaginary

Ans:

(2) Positive

Light Question 22

       The radius o curvature of a mirror is 20 cm the focal length is :

(1) 20 cm

(2) 10 cm

(3) 40 cm

(4) 5 cm

Ans:

(2) 10 cm

Light Question 23

       Image formed by plane mirror is always :

(1) Real and erect

(2) Real and inverted

(3) Virtual and erect

(4) Virtual and inverted

Ans:

(3) Virtual and erect

Long Answer Type Questions

(1)Define spiracle mirror. Derive the formula connecting object distance image distance and focal length for the mirror.

(2)Write the formation of image by convex lens and concave lens is different situations. Draw relevant diagrams.

(3)Write the types of lenses. Using the diagram, derive the relation between object distance, image distance and focal length of a lens.

(4)Derive the relation between u, v and R for a convex spherical surface, when a ray of light is going from rarer to denser medium. Draw appropriate diagram.

(5)Draw a labelled diagram to illustrate the action of compound microscope for near point of the eye.

(6) Draw a diagram to show refraction by prism for the

monochromatic light source. Derive the relation between angle of prism and minimum deviation angle in terms of refractive index of glass. 

(7) Assuming lens to be two spherical surface derive relation between u, v and f.

(8) Write the types of telescope. For refractive telescope derive relation for magnifying power. Also discuss about its construction and working.