You are given kerosene, turpentine and water. In which of these does the light travel fastest? Use the information given in Table.
Solution and Explanation
Speed of light in a medium is given by the relation for refractive index (nm). The relation is given as
\(n_m = \frac{\text{Speed of light in air }}{\text{Speed of light in the medium}} =\frac{ c }{v}\)
\(⇒v=\frac{c}{n_m}\)
\(⇒ v∝\frac{1}{n_m}\)
It can be inferred from the relation that light will travel the slowest in the material which has the highest refractive index and travel the fastest in the material which has the lowest refractive index.
It can be observed from table that the refractive indices of kerosene, turpentine, and water are 1.44, 1.47, and 1.33 respectively. Therefore, light travels the fastest in water.
Top Questions on Refraction of Light
A parallel beam of light travelling in air (refractive index \(1.0\)) is incident on a convex spherical glass surface of radius of curvature \(50 \, \text{cm}\). Refractive index of glass is \(1.5\). The rays converge to a point at a distance \(x \, \text{cm}\) from the centre of curvature of the spherical surface. The value of \(x\) is ___________.
- JEE Main - 2026
- Physics
- Refraction of Light
- In YDSE, slit separation $d = 2$ mm, distance between slits and screen $D = 10$ m. Wavelength of light is $\lambda = 6000$\AA. If intensity of light through each slit is $I_0$, find intensity at point directly in front of one of the slits.
- JEE Main - 2026
- Physics
- Refraction of Light
Two light beams fall on a transparent material block at point 1 and 2 with angle \( \theta_1 \) and \( \theta_2 \), respectively, as shown in the figure. After refraction, the beams intersect at point 3 which is exactly on the interface at the other end of the block. Given: the distance between 1 and 2, \( d = 4/3 \) cm and \( \theta_1 = \theta_2 = \cos^{-1} \frac{n_2}{2n_1} \), where \( n_2 \) is the refractive index of the block and \( n_1 \) is the refractive index of the outside medium, then the thickness of the block is cm.
- JEE Main - 2025
- Physics
- Refraction of Light
Two light beams fall on a transparent material block at point 1 and 2 with angle \( \theta_1 \) and \( \theta_2 \), respectively, as shown in the figure. After refraction, the beams intersect at point 3 which is exactly on the interface at the other end of the block. Given: the distance between 1 and 2, \( d = 4/3 \) cm and \( \theta_1 = \theta_2 = \cos^{-1} \frac{n_2}{2n_1} \), where \( n_2 \) is the refractive index of the block and \( n_1 \) is the refractive index of the outside medium, then the thickness of the block is cm.
- JEE Main - 2025
- Physics
- Refraction of Light
- At the interface between two materials having refractive indices \( n_1 \) and \( n_2 \), the critical angle for reflection of an EM wave is \( \theta_c \). The \( n_1 \) material is replaced by another material having refractive index \( n_3 \), such that the critical angle at the interface between \( n_1 \) and \( n_3 \) materials is \( \theta_{c3} \). If \( n_1 > n_2 > n_3 \), \( \frac{n_2}{n_3} = \frac{2}{5} \), and \( \sin \theta_{c2} - \sin \theta_{c1} = \frac{1}{2} \), then \( \theta_{c1} \) is:
- JEE Main - 2025
- Physics
- Refraction of Light
Questions Asked in CBSE X exam
Read the following sources of loan carefully and choose the correct option related to formal sources of credit:
(i) Commercial Bank
(ii) Landlords
(iii) Government
(iv) Money Lende- CBSE Class X - 2025
- Money and Credit
- Rama is a farmer. She needs loan for agriculture work. Which of the following sources of loan will be beneficial for Rama? Choose the most appropriate option. I. Bank
II. Agricultural Trader
III. Self-Help Group
IV. Government- CBSE Class X - 2025
- Money and Credit
- Two statements are given below. They are Assertion (A) and Reason (R). Read both the statements carefully and choose the correct option:
Assertion (A): Rupees is accepted as medium of exchange in India.
Reason (R): The World Bank legalises the use of rupee as a medium of payment in India.- CBSE Class X - 2025
- Money and Credit
- Two statements are given below. They are Assertion (A) and Reason (R). Read both the statements carefully and choose the correct option. Assertion (A): Rupees is accepted as medium of exchange in India.
Reason (R): The World Bank legalises the use of rupee as a medium of payment in India.- CBSE Class X - 2025
- Money and Credit
- Rama is a farmer. She needs loan for agriculture work. Which of the following sources of loan will be beneficial for Rama? Choose the most appropriate option:
I. Bank
II. Agricultural Trader
III. Self-Help Group
IV. Government- CBSE Class X - 2025
- Money and Credit