A set of multiple-choice questions with answers from the topic Light. A comprehensive general knowledge test for class 9-10.
[MCQ-1] What is the relation between focal length (f) and radius of curvature (r) of a curve mirror?
A: f = 2r
B: f = r/2
C: f = r/3
D: f = 3r/2
Answer
f =2r
[MCQ-2] What is the focal length of a curve mirror is it has a radius of curvature is 40 cm.
A: 20 cm
B: 35 cm
C: 25 cm
D: 40 cm
Answer
20 cm
[MCQ-3] Which type of mirror used in the headlight of a motorcycle?
A: Concave mirror
B: Convex mirror
C: Flat mirror
D: none of the above
Answer
Concave mirror
[MCQ-4] Which type of mirror used in the dental clinic?
A: Concave mirror
B: Convex mirror
C: Flat mirror
D: None of the above
Answer
Concave mirror
[MCQ-5] If a beam of red light and a beam of violet light are incident at the same angle on the inclined surface of a prism from air medium and produce angles of refraction r and v respectively, which of the following is correct?
A: r = v
B: r > v
C: r = 1/v
D: r < v
Answer
D: r < v
[MCQ-6] A point source of light is placed at the centre of curvature of a concave mirror. The angle of deviation of the rays incident on the mirror from this source and reflected from it is
A: 0
B: 180 degrees
C: 90 degrees
D: 360 degrees
Answer
B: 180 degrees
[MCQ-7] What kind of mirror is this?
fig 1A: Convex mirror
B: Concave mirror
C: Plano Concave
D: Concavo Convex
Answer
Concave mirror
[MCQ-8] In the above figure – 1, the point P represents —
A: Pole
B: Center of curvature
C: Focus point
D: None of these
Answer
Pole
[MCQ-9] In the above figure – 1, what the point f indicates?
A: Pole
B: Center of curvature
C: Focus point
D: None of these
Answer
Focus point
[MCQ-10] In the above figure – 1, the point C represents-
A: Pole
B: Center of curvature
C: Focus point
D: None of these
Answer
Center of Curvature
[MCQ-11] Which among the following figure is correct regarding the reflection of light by a concave mirror?
A: Figure 1 is correct
B: Figure 2 is correct
C: Figure 3 is correct
D: None of the figure is correct
Answer
Figure 1 is correct
[MCQ-12] What kind of lense is the following figure given below?
A: Concave Lens
B: Plano-Concave Lens
C: Convex lens
D: Concevo-Convex Lens;
Answer
Convex Lens
[MCQ-13] Which of the following figure given below is correct?
A: Figure 1 is correct
B: Figure 2 is correct
C: Figure 3 is correct
D: Figure 4 is correct
Answer
Figure 1 is correct
[MCQ-14] In case of refraction, if the angle of incidence and the angle of refraction are 45 degrees and 30 degrees respectively, then the angle of deviation is
A: 75 o
B: 15o
C: 7.5o
D: 37.5o
Answer
B: 15o
[MCQ-15] Which of the following has the highest wavelength?
A: X-Ray
B: Gamma ray
C: infrared ray
D: ultraviolet ray
Answer
Infrared ray
[MCQ-16] To produce a real and magnified image by a convex lens, where should the object be placed? [f= focus; u= distance of the object from the lens]
A: f < u < 2f
B: u < 2f
C: u > 2f
D: u > f
Answer
A: f < u < 2f
[MCQ-17] If a refractive index of a medium is μ, and the velocity of a light in free space is c, then the velocity of light of that medium is
A: μc
B: (c/μ)1/2
C: (μc)1/2
D: c/μ
Answer
D: c/μ
[MCQ-18] When the light is passing from rarer to a denser medium, which is the correct statement?
A: Incident angle is equal to refracted angle
B: Incident angle is greater than refracted angle
C: Incident angle is less than refracted angle
D: Can not be determined
Answer
B: Incident angle is greater than refracted angle
[MCQ-19] Which physical quantity is remain constant in case refraction?
A: Wavelength of light
B: Frequency of light
D: Amplitude
E: All of the above
Answer
B: Frequency of light
[MCQ-20] In case of refraction, when the light passes from rarer to a denser medium, if the angle of incident is 65o and angle of refraction is 25o, then the deviation of angle would be-
A: 65o
B: 25o
C: 40o
D: 30o
Answer
C: 40o
[MCQ-21] The deviation of light ray when refracted by a parallel glass slab is –
A: 90 o
B: 0o
C: 45o
D: 180o
Answer
B: 0o
[MCQ-22] An object is placed at a distance u from a convex lens, and its image is formed at a distance v. What will be the formula of lateral magnification (m)?
A: m = uv
B: m = u/v
C: m= v/u
D: m= (u/v)1/2
Answer
C: m= v/u
[MCQ-23] What is the relation between the radius of curvature and the focal length of a mirror?
A: f = 3/r
B: f = r/3
C: f = 2r
D: f= r/2
Answer
D: f= r/2
[MCQ-24] The refractive index of a medium with respect to vacuum is
A: Always greater than one
B: Always less than one
C: Equal to one
D: none of the above
Answer
B: Always less than one.
[MCQ-25] Which color has the maximum deviation when white color refracted through a prism?
A: Red
B: Violet
C: Green
D: Yellow
Answer
B: Violet
[MCQ-26] What will be the refractive index of a medium when the velocity of light is 2 × 108 m/s?
A: 1
B: 1.2
C: 1.5
D: 1.7
Answer
C: 1.5
[MCQ-27] Which among the following electromagnetic wave the frequency is maximum?
A: Infrared
B: Ultraviolet
C: X-ray
D: Gama Ray
Answer
D: Gama Ray
[MCQ-28] What type of image will be formed if an object is placed between f and 2f in front of a convex lens?
A: Real and enlarged upright
B: Real and diminished
C: Virtual, enlarged and upright
D: Real, enlarged, inverted
Answer
D: Real, enlarged, inverted
[MCQ-29] For White light which color has the maximum refractive index?
A: Red
B: Yellow
C: Orange
D: Violet
Answer
D: Violet
[MCQ-30] What will be the angle of refraction for a ray of light fall perpendicular to the interface of two mediums?
A: 90o
B:0o
C: 180o
D: 45o
Answer
B: 0o
[MCQ-31] What will be the refractive index of a medium if a light ray falls normally on it?
A: One
B: one half
C: 3/2
D: infinity
Answer
D: Infinity
[MCQ-32] Snell’s law is valid for
A: Reflection of light
B: Refraction of light
C: Both A and B
D: None of A and B
Answer
B: Refraction of light
[MCQ-33] Let ∠i = angle of incidence, ∠r = angle of refraction, and μ = refractive angle. The correct formula for Snell”s law is –
A: μ = sin∠i × sin∠r
B: μ = sin∠i × cos∠r
C: μ = (sin∠i)/(sin∠r)
D: μ = (sin∠r)/(sin∠i)
Answer
C: μ = sin∠i/sin∠r
[MCQ-34] The color of light depends on
A: Wavelength
B: Frequency
C: Amplitude
D: All of the above
Answer
B: Frequency
[MCQ-35] Between red and violet, which color has more frequency?
A: Red has more frequency than violet
B: Violet has more frequency than red
C: Red and violet has the same frequency
D: Can not say
Answer
B: Violet has more frequency than red
[MCQ-36] Between red and violet, which color has greater wavelength?
A: Red has a greater wavelength than violet.
B: Violet has a greater wavelength than red.
C: Red and violet have the same wavelength.
D: Can not say
Answer
A: Red has a greater wavelength than violet.
[MCQ-37] Let frequency = n, wavelength = λ, and the velocity of light is c. Which relation among the following is correct?
A: c = nλ
B: c = n/λ
C: c = λ/n
D: c = n2/λ
Answer
A: c = nλ
[MCQ-38] For which of the following color does a lens has maximum focal length?
A: Red
B: Yellow
C: Green
D: Violet
Answer
A: Red
[MCQ-39] For an object placed at the focus of a convex lens the image will be formed at
A: Focus
B: Optical center
C: Infinity
D: Twice the length of focus
Answer
Infinity
[MCQ-40] A convex mirror is used
A: by a dentist
B: for shaving
C: as a review mirror of a vehicle
D: as a light reflector for obtaining a parallel beam of light
Answer
C
[MCQ-41] Choose whether the statement is true or false: Focal length of a lens depends on its surrounding medium.
A: true
B: false
Answer
True
[MCQ-42] To obtain parallel ray from a point light source we use
A: both convex lens and concave mirror
B: both convex lens and convex mirror
C: both concave lens and concave mirror
D: both concave lens and convex mirror
Answer
A: both convex lens and concave mirror
[MCQ-43] What is the type of image form on the retina of our eyes?
A: Real and upright
B: Virtual and upright
C: Real and inverted
D: Virtual and inverted
Answer
Real and inverted
[MCQ-44] Which color is used as danger sign?
A: Green
B: Brown
C: Orange
D: Red
Answer
Red
[MCQ-45] For danger sign, red color is used, because
A: Scattering of red color is less due to large wavelength
B: Scattering of red color is less due to small wavelength
C: Scattering of red color is greater due to large wavelength
D: Scattering of red color is greater due to small wavelenth
Answer
A: Scattering of red color is less due to large wavelength
[MCQ-46] 4 different mediums P, Q, R and S have refractive index 1.5, 1.4, 1.8, and 1.3 respectively. In which medium the light has the maximum speed?
A: P medium
B: Q medium
C: R medium
D: S medium
Answer
S medium
[MCQ-47] Let μr and μv are the refractive indexes of a medium of red and violet color respectively. Then
A: μr > μv
B: μr < μv
C: μr = μv
D: None of the above
Answer
B: μr < μv
[MCQ-48] Focal length of a convex lens is 15 cm. For which distance an object is placed so that the lens acts as a magnifying glass?
A: Between 15 cm and 30 cm
B: Less than 15 cm
C: Greater than 30 cm
D: Exactly at 30 cm
Answer
B: Less than 15 cm
[MCQ-49] = deviation of prism, i1 = angle of incidence, i2 = angle of refraction of a prism. Which formula is correct?
A: = i1 + i2 − A
B: = i1 + i2 + A
C: = i1 − i2 + A
D: = (i1 + i2)/A
Answer
A
[MCQ-50] Deviation of light passing through the center of lens is
A: 0°
B: 45°
C: 90°
D: 180°
Answer
A: 0°
[MCQ-51] The split of white light into 7 colors by prism is known as
A: Diffraction
B: Dispersion
C: scattering
D: Polarization
Answer
B: Dispersion
[MCQ-52] What is the speed of light in free space?
A: 3.5 ×108 m/s
B: 3 ×108 m/s
C: 3 ×109 m/s
D: 3.5 ×109 m/s
Answer
B: 3 ×108 m/s
These are the most common MCQs from light you need to practice. You may download the set of these questions with answers as pdf format.
Note: All the MCQs on light are important for any competitive examination. These multiple choice question answers from light (optics) are very useful for class 9 and class 10.