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Class 10 Light — Reflection and Refraction worksheet
CBSE Science. Mirror and lens formulas, magnification, refractive index, power. Every sheet has 20 questions in three sections and an answer key, and the numbers change every time.
Sample questions
Real questions from this chapter, as the app sets them. Tap Answer to see the answer and working.
Section A · multiple choice
- 1.
The radius of curvature of a concave mirror is 24 cm. Its focal length is:
- −24 cm
- 12 cm
- −13 cm
- −12 cm
Answer
(d) −12 cm
f = R/2, negative for a concave mirror
- 2.
A concave lens has a focal length of −200 cm. Its power is:
- −0.5 D
- 0.5 D
- −0.01 D
- −200 D
Answer
(a) −0.5 D
P = 1 ÷ f (in m) = 100 ÷ −200
- 3.
Light travels at 3 × 10⁸ m/s in vacuum and 2.4 × 10⁸ m/s in a medium. The refractive index of the medium is:
- 1.75
- 2.4
- 3
- 1.25
Answer
(d) 1.25
n = c ÷ v = 3 ÷ 2.4
Section B · short answer
- 4.
An object is 60 cm in front of a concave mirror of focal length 10 cm. Find the position and nature of the image.
Answer
v = −12 cm (in front of the mirror); real, inverted and diminished
1/v = 1/f − 1/u gives v = −12 cm; m = −v/u = −0.2
- 5.
An object is 18 cm in front of a convex mirror of focal length 36 cm. Find the position and nature of the image.
Answer
v = 12 cm (behind the mirror); virtual, erect and diminished
1/v = 1/f − 1/u gives v = +12 cm; m = 0.67
Section C · long answer
- 6.
A 8 cm tall candle stands 48 cm in front of a concave mirror of focal length 40 cm. Where should a screen be placed to get a sharp image? Describe the image and find its height.
Answer
240 cm in front of the mirror; real, inverted and magnified; height 40 cm
v = −240 cm; m = −5; h′ = m × 8
Fresh sheets for your child
In the app, every Light — Reflection and Refraction sheet is new: the app remembers the questions your child has already had and leaves them out. Print the sheet as a PDF, or use notebook mode and write the answers in a notebook.
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