✓ Board-verified
Science · 2024 · 2 marks
CBSE 2024 · Region 2 · Set 1 · Q24
(a) State two laws of refraction of light.
(a)
State two laws of refraction of light.
OR
(b)
Define the term absolute refractive index of a medium. A ray of light enters from vacuum to glass of absolute refractive index 1.5. Find the speed of light in glass. The speed of light in vacuum is $\displaystyle 3 \times 10^{8} \mathrm{~m} / \mathrm{s}$.
Marking-scheme solution
Laws of Refraction of light :
(i)
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.
(ii)
The ratio of the 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.
Absolute refractive index of a medium is the ratio of speed of light in
air/vacuum to the speed of light in the given medium.
Given:
\[\mathrm{c}=3 \times 10^{8} \mathrm{~m} / \mathrm{s} ; \mathrm{n}_{\mathrm{m}}=1 \cdot 5 ; \mathrm{v}_{\mathrm{m}}=?
\]
Absolute refractive index of a medium $\displaystyle \left(\mathrm{n}_{\mathrm{m}}\right)$
\[\begin{aligned}
& =\frac{\text { speed of light in vacuum }}{\text { speed of light in medium }}=\frac{c}{v_{m}}
\mathrm{v}_{\mathrm{m}}=\frac{c}{n_{m}}=2 \times 10^{8} \mathrm{~m} / \mathrm{s} &
\end{aligned}
\]
All Light - Reflection and Refraction questions2024 question paperNCERT solutions: Light - Reflection and RefractionPractice Light - Reflection and Refraction →
More from Light - Reflection and Refraction
- With the help of above given ray diagram, calculate the angle of refraction. Given that the refractive index of Medium 2 with respect to Medium 1 is…2026
- A student wants to obtain an erect image of an object using a concave mirror of 10 cm focal length. What will be the distance of the object from…2023
- An object is kept at a distance of 1m from a lens of power+2D: (i) Identify the type of lens. (ii) Calculate its focal length and distance of the…2023
- If the absolute refractive indices of two media X and Y are 6/5 and 4/3 respectively, then the refractive index of Y with respect to X will be:2025
- A student wants to project the image of a candle flame on a screen 60 cm in front of a mirror by keeping the candle at a distance of 15 cm from its…2023
- An object is placed in front of a concave mirror of focal length 12 cm. If distance of the object from the pole of the mirror is 8 cm, then use…2024
- (i) "In refraction of light through a rectangular glass slab, the emergent ray is always parallel to the direction of the incident ray." Why? Explain…2025
- The above ray diagram is to show image formation by a reflecting telescope. Reflecting telescope revolutionized our way of looking into the sky.…2026
CBSE Class 10 Science past-paper question from the 2024 board exam, with the answer as CBSE’s own marking scheme gives it. Where our answers come from.