Optics One Mark Online Test — Class 10 Science

Optics One Mark Online Test (10th Standard Science)

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The refractive index of four substances A, B, C and D are 1.31, 1.43, 1.33, 2.4 respectively. The speed of light is maximum in

A.Substance A B.Substance B C.Substance C D.Substance D

Where should an object be placed so that a real and inverted image of same size is obtained by a convex lens?

A.at f B.at 2f C.infinity D.between f and 2f

A small bulb is placed at the principal focus of a convex lens. When the bulb is switched on, the lens will produce

A.a convergent beam of light B.a divergent beam of light C.a parallel beam of light D.a coloured beam of light

Magnification of a convex lens is

A.positive B.negative C.either positive or negative D.zero

A convex lens forms a real, diminished point sized image at focus. Then the position of the object is at

A.focus B.infinity C.at 2f D.between f and 2f

Power of a lens is -4D, then its focal length is

A.4 m B.-40 m C.-0.25 m D.-2.5 m

In a myopic eye, the image of the object is formed

A.behind the retina B.on the retina C.in front of the retina D.on the blind spot

The eye defect 'presbyopia' can be corrected by

A.convex lens B.concave lens C.convex mirror D.bifocal lenses

Which of the following lens would you prefer to use while reading small letters found in a dictionary?

A.A convex lens of focal length 5 cm B.A concave lens of focal length 5 cm C.A convex lens of focal length 10 cm D.A concave lens of focal length 10 cm

Q10

If VB, VG, VR be the velocity of blue, green and red light respectively in a glass prism, then which of the following statement gives the correct relation?

A.VB = VG = VR B.VB > VG > VR C.VB < VG < VR D.VB < VG > VR

Q11

When a ray of light passes from a medium of refractive index 1.5 into a medium of refractive index 1.3, how does its speed and direction change?

A.Its speed decreases and it bends towards the normal B.Its speed increases and it bends away from the normal C.Its speed decreases and it bends away from the normal D.Its speed increases and it bends towards the normal

Q12

According to Rayleigh's scattering law, if the wavelength of light is reduced to half of its original value, by what factor will the amount of scattering change?

A.It will decrease to 1/16 of its original value B.It will increase by a factor of 4 C.It will increase by a factor of 16 D.It will decrease to 1/4 of its original value

Q13

Which type of scattering is primarily responsible for the white appearance of clouds when sunlight falls on water droplets?

A.Rayleigh scattering B.Mie scattering C.Tyndall scattering D.Raman scattering

Q14

In Raman scattering, the scattered light contains additional spectral lines of frequencies other than the incident frequency. This phenomenon is observed when monochromatic light passes through which of the following?

A.Only gases B.Only liquids C.Only transparent solids D.Gases, liquids, or transparent solids

Q15

According to the Cartesian sign convention, which of the following distances is always taken as negative for spherical lenses?

A.Focal length of a convex lens B.Distance of the object from the lens C.Distance of a real image formed behind the lens D.Height of an erect object placed above the principal axis

Q16

If the magnification produced by a spherical lens is -0.5, what is the nature and size of the image formed?

A.Real, inverted and enlarged B.Real, inverted and diminished C.Virtual, erect and enlarged D.Virtual, erect and diminished

Q17

Which part of the human eye acts as the main refracting surface where most of the refraction of entering light occurs?

A.Iris B.Pupil C.Cornea D.Retina

Q18

The power of accommodation of the human eye is achieved by changing the focal length of the eye lens. This is done with the help of which of the following?

A.Optic nerves B.Ciliary muscles C.Iris muscles D.Sclera

Q19

What is the maximum time interval between two consecutive light pulses below which the human eye cannot distinguish them separately?

A.1/10 second B.1/16 second C.1/25 second D.1/50 second

Q20

A person suffering from myopia can see objects clearly only up to a distance of 5 meters. To see distant objects at infinity, what should be the focal length of the correcting lens?

A.+5 meters B.-5 meters C.-2.5 meters D.+2.5 meters

Q21

An eye defect where a person cannot see parallel and horizontal lines clearly is called astigmatism. This defect can be corrected by using which type of lens?

A.Bifocal lenses B.Cylindrical lenses C.Convex lenses D.Concave lenses

Q22

A simple microscope consists of which of the following optical components?

A.A concave lens of short focal length B.A convex lens of short focal length C.A concave lens of long focal length D.A convex lens of long focal length

Q23

In a compound microscope, how do the focal lengths of the objective lens and the eye lens compare?

A.Objective lens has larger focal length, eye lens has shorter focal length B.Objective lens has shorter focal length, eye lens has larger focal length C.Both lenses have equal and short focal lengths D.Both lenses have equal and long focal lengths

Q24

If a lens has a focal length of -25 centimeters, what is its power?

A.+4 D B.-4 D C.+0.04 D D.-0.04 D

Q25

When white light is refracted through a glass prism, why does a spectrum form?

A.Because different colored lights travel with the same velocity in glass B.Because the refractive index of glass is different for different wavelengths C.Because red light has the highest angle of refraction and violet has the smallest D.Because the prism reflects only certain colors of the white light

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About this Optics test

This free online practice test covers Optics from the 10th Standard Science (Samacheer Kalvi) syllabus. Choose the number of questions and an optional time limit, then answer and submit — everything is checked in your browser, with the correct answers and a worked explanation shown at the end. For the full solutions to every question in this set, see the solved MCQs page.

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