Bihar Board Class 10 · Science · Matric exam 2027
Chapter 10: Light – Reflection and Refraction
This chapter’s questions from Bihar Board (BSEB)’s real papers of 2021–2026 — the 19 asked most often, 3 with the full model answer, 16 with how the answer begins — and objective questions with the board’s key.
- marks a year (about)
- 8
- questions a year (about)
- 11
- rank in Science
- #2
From 6 years of papers, 2021–2026 · full chapter-wise marks
VVI questions — the ones the board asked most (19)
- Q1Short answer2 marksAsked: 2021, 2025
Why does the coin placed in water appear raised?
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Model answer · refraction, coin in water
- 1.The coin placed in water appears raised due to refraction of light. The light reaching our eyes from the coin seems to come from a different direction than its actual position, so we see an apparent image of the coin which is raised above its actual position.1 mark
- 2.The coin lies in water which is a denser medium, and the light rays travel from this denser medium (water) to air, which is a rarer medium, before reaching our eyes. While travelling obliquely from the denser medium to the rarer medium, the light rays bend away from the normal, and this bending causes the coin to appear raised.1 mark
- Write the phrase 'refraction of light' and mention the 'apparent' raised position of the coin in the first paragraph.
- Clearly name water as the denser medium and air as the rarer medium while describing the bending of light rays.
- State that the light ray bends 'away from the normal' while going from water to air.
Marks split from a structure derived from past papers (checked twice); not Bihar Board’s official scheme
- Q2Short answer2 marksAsked: 2022, 2026
Write any two uses of concave mirror.
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Model answer · uses of concave mirror
- 1.Concave mirrors are often used as shaving mirrors to see a larger image of the face.1 mark
- 2.Concave mirrors are commonly used in torches, search-lights and vehicles headlights to get powerful parallel beams of light.1 mark
- Write 'shaving mirror' and 'larger image of the face' for the first use.
- Write 'headlights' and 'powerful parallel beams of light' for the second use.
- Give exactly two uses as asked, not more.
Marks split from a structure derived from past papers (checked twice); not Bihar Board’s official scheme
- Q3Short answer2 marksAsked: 2023, 2026
Why is a concave lens called a diverging lens ?
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Model answer · diverging action, concave lens
- 1.A concave lens spreads out the light rays coming parallel to its principal axis after refraction. Several rays of light parallel to the principal axis fall on a concave lens, and these rays, after refraction from the lens, appear to diverge from a point on the principal axis.1 mark
- 2.Due to this property of diverging the light rays, a concave lens is called a diverging lens.1 mark
- Mention that parallel rays falling on the concave lens, after refraction, appear to diverge from a point on the principal axis.
- End by clearly stating that this diverging property is why the concave lens is called a diverging lens.
Marks split from a structure derived from past papers (checked twice); not Bihar Board’s official scheme
- Q4Long answer6 marksAsked: 2021
The radius of curvature of a convex mirror which is used to see the back view in any automobile is 5 m. If a bus is at a distance of 5m, then find the position, nature and size of the image.
How the model answer begins
1. The radius of curvature of the convex mirror is R = +5 m, taking the positive sign because for a convex mirror the radius of curvature is behind the mirror. The focal length is given by f = R/2, so f = +5/2 = +2.5 m.
The full answer from Medha Ma’am → - Q5Long answer6 marksAsked: 2024
Define focus of a concave spherical mirror. Prove that in a concave mirror R = 2f.
How the model answer begins
1. The point on the principal axis where light rays parallel to the principal axis converge after reflection is called the principal focus of a concave mirror. It is represented by the letter F, and the distance between…
The full answer from Medha Ma’am → - Q6Long answer6 marksAsked: 2025
Describe a method to find the focal length of a convex lens.
How the model answer begins
1. To find the focal length of a convex lens, the convex lens is placed on a lens stand and mounted on an optical bench, with its optical centre lying over the central line of the optical bench.
The full answer from Medha Ma’am → - Q7Long answer6 marksAsked: 2026
How will you identify the given convex lens, concave lens and a circular glass plate without touching their surfaces ?
How the model answer begins
1. To identify the given lenses and the circular glass plate without touching their surfaces, each one is placed, one by one, directly over some printed material, such as a page with small letters, and the letters are…
The full answer from Medha Ma’am → - Q8Long answer6 marksAsked: 2022
In a concave mirror prove that 1/v + 1/u = 1/f.
How the model answer begins
1. Take a concave mirror with pole P, principal focus F and centre of curvature C on its principal axis. An object AB is placed perpendicular to the principal axis, between the centre of curvature and infinity. The ray…
The full answer from Medha Ma’am → - Q9Short answer2 marksAsked: 2021
What should be the position of an object in front of convex lens for virtual and magnified image ? Draw a neat diagram.
How the model answer begins
1. The object must be placed between the optical centre O and the principal focus F₁ of the convex lens.
The full answer from Medha Ma’am → - Q10Short answer2 marksAsked: 2024
What is a simple microscope ? Draw its ray diagram.
How the model answer begins
1. A simple microscope is a convex lens of short focal length which is used to see small objects in a magnified form.
The full answer from Medha Ma’am → - Q11Short answer2 marksAsked: 2024
What is the law of refraction of light ?
How the model answer begins
1. The incident ray, the refracted ray and the normal to the interface of two transparent media at the point of incidence, all lie in the same plane.
The full answer from Medha Ma’am → - Q12Short answer2 marksAsked: 2025
What is called absolute refractive index?
How the model answer begins
1. The absolute refractive index of a medium is the ratio of the speed of light in vacuum to the speed of light in the medium. If the first medium is vacuum or air, the refractive index of the second medium found with…
The full answer from Medha Ma’am → - Q13Short answer2 marksAsked: 2025
What is light beam? How many types of it are there?
How the model answer begins
1. A group of light rays is called a beam of light.
The full answer from Medha Ma’am → - Q14Short answer2 marksAsked: 2026
What do you understand by the power of a lens ? Write its SI unit.
How the model answer begins
1. The power of a lens is a measure of its ability to converge or diverge light rays, which is equal to the reciprocal of its focal length. It is represented by the letter P and is given by P = 1/f, where f is the focal…
The full answer from Medha Ma’am → - Q15Short answer2 marksAsked: 2026
Write down Snell's law.
How the model answer begins
1. The ratio of sine of angle of incidence to the sine of angle of refraction is a constant, for the light of a given colour and for the given pair of media. This law is also known as Snell's law of refraction.
The full answer from Medha Ma’am → - Q16Short answer2 marksAsked: 2022
Why is a convex lens called a converging lens ?
How the model answer begins
1. When several rays of light parallel to the principal axis fall on a convex lens, these rays, after refraction from the lens, converge to a point on the principal axis.
The full answer from Medha Ma’am → - Q17Short answer2 marksAsked: 2022
How will you identify the nature of a spherical mirror?
How the model answer begins
1. The nature of a spherical mirror can be identified by placing an object in front of it and comparing the size of the image formed with the size of the object. If the image size is equal to the object size, the mirror is…
The full answer from Medha Ma’am → - Q18Short answer2 marksAsked: 2021
Find the power of a concave lens of 2 m focal length.
How the model answer begins
1. The focal length of the concave lens is given as 2 m. Since the power of a convex lens is positive and that of a concave lens is negative, the focal length of the concave lens, f = -2 m.
The full answer from Medha Ma’am → - Q19Short answer2 marksAsked: 2025
What is called absolute refractive index ?
How the model answer begins
1. The absolute refractive index of a medium is the ratio of the speed of light in vacuum to the speed of light in the medium. When light travels from vacuum or air into a medium, this refractive index is called the…
The full answer from Medha Ma’am →
Objective questions with the board’s key (10)
- 1. Bihar Board 2026
When the object is at focus, then the image formed in a concave mirror is
- (A) Real and at centre
- (B) Virtual
- (C) At infinity ✓
- (D) No image is formed
Answer: (C)
- 2. Bihar Board 2026
Image formed by plane mirror is lateral inverted, i.e.
- (A) left appears right ✓
- (B) erect means inverted
- (C) large in size
- (D) none of these
Answer: (A)
- 3. Bihar Board 2026
In concave mirror, image formed at the focus is
- (A) Real and inverted ✓
- (B) Virtual and erect
- (C) Real and erect
- (D) Virtual and inverted
Answer: (A)
- 4. Bihar Board 2026
When an object is at infinity, the image in concave mirror is
- (A) Behind the mirror, virtual
- (B) At focus, real, inverted ✓
- (C) At centre, virtual
- (D) At pole, virtual
Answer: (B)
- 5. Bihar Board 2026
The value of magnification produced by plane mirror is always
- (A) >1
- (B) <1
- (C) =1 ✓
- (D) 0
Answer: (C)
- 6. Bihar Board 2026
Refraction of light occurs because of
- (A) Change in speed of light ✓
- (B) Change in frequency
- (C) Change in colour
- (D) None of these
Answer: (A)
- 7. Bihar Board 2026
The unit of refractive index is
- (A) m/s
- (B) no unit ✓
- (C) m
- (D) cm
Answer: (B)
- 8. Bihar Board 2026
The speed of light in air is approximately
- (A) 3 x 10^4 m/s
- (B) 3 x 10^5 m/s
- (C) 3 x 10^6 m/s
- (D) 3 x 10^8 m/s ✓
Answer: (D)
- 9. Bihar Board 2026
The reason responsible for apparent bending of a stick in water is
- (A) Reflection
- (B) Refraction ✓
- (C) Dispersion
- (D) Scattering
Answer: (B)
- 10. Bihar Board 2026
Which of the following has the highest refractive index ?
- (A) Water
- (B) Diamond ✓
- (C) Glass
- (D) Air
Answer: (B)
Questions parents and students ask
- How many marks does "Light – Reflection and Refraction" carry in Bihar Board Class 10 Science?
- In the Bihar Board papers of 2021–2026, this chapter carried about 8 marks and about 11 questions a year; by marks it ranks 2 in Science.
- Which are the most important (VVI) questions of "Light – Reflection and Refraction"?
- The 19 questions above are from the board’s real papers, each with the years it was asked; the most-asked come first with their full model answers. All 19 written questions of this chapter, with answers, are in the AskMedha app.
- Do the answers follow the board’s marking scheme?
- BSEB does not publish a marking scheme. Each answer is written point by point on a structure derived from past papers and checked by a second, independent model; it is never called the board’s official scheme.
The same preparation, with Medha Ma’am — on your phone
Every question of every chapter with its model answer, practice questions in the board’s own shapes, 60 minutes of class a day, written answers marked, a test every Sunday and a WhatsApp report to parents.
Medha Ma’am is an AI teacher, not a live tutor. Every answer is checked twice; a person takes responsibility.