The refractive index of glass is 1.5. The speed of light in air is \(3 \times 10^8\) m/s. The speed of light in glass will be
Show Hint
- \(3 \times 10^8\) m/s
- \(2 \times 10^8\) m/s
- \(4.5 \times 10^8\) m/s
- \(2.25 \times 10^8\) m/s
The Correct Option is B
Solution and Explanation
Step 1: Understanding the Formula for Speed of Light in a Medium
The speed of light in any medium is given by the formula:
\[
v = \frac{c}{n}
\]
where:
- \(v\) is the speed of light in the medium
- \(c\) is the speed of light in vacuum (which is \(3 \times 10^8\) m/s)
- \(n\) is the refractive index of the medium
Step 2: Applying the Formula
Given that the refractive index of glass is \(n = 1.5\), and the speed of light in air is \(c = 3 \times 10^8\) m/s, we can calculate the speed of light in glass as:
\[
v = \frac{3 \times 10^8}{1.5} = 2 \times 10^8 \, \text{m/s}
\]
Step 3: Conclusion
Thus, the speed of light in glass is \(2 \times 10^8\) m/s. The correct answer is option (B).
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 UP Board X exam
- Colour origin from
- UP Board X - 2025
- Light and Colour
- How many national political parties are there in India?
- UP Board X - 2025
- Parties and the Party Systems in India
- Prime factorisation of 156 will be:
- UP Board X - 2025
- Number System
- (i) Food chain
(ii) Growth hormone in human.- UP Board X - 2025
- Food Chains and Energy Flow
The following table shows the ages of the patients admitted in a hospital during a year. Find the mode and the median of these data.
\[\begin{array}{|c|c|c|c|c|c|c|} \hline Age (in years) & 5-15 & 15-25 & 25-35 & 35-45 & 45-55 & 55-65 \\ \hline \text{Number of patients} & \text{6} & \text{11} & \text{21} & \text{23} & \text{14} & \text{5} \\ \hline \end{array}\]- UP Board X - 2025
- Mean, median, mode and standard deviation