- Trending Categories
- Data Structure
- Networking
- RDBMS
- Operating System
- Java
- MS Excel
- iOS
- HTML
- CSS
- Android
- Python
- C Programming
- C++
- C#
- MongoDB
- MySQL
- Javascript
- PHP
- Physics
- Chemistry
- Biology
- Mathematics
- English
- Economics
- Psychology
- Social Studies
- Fashion Studies
- Legal Studies

- Selected Reading
- UPSC IAS Exams Notes
- Developer's Best Practices
- Questions and Answers
- Effective Resume Writing
- HR Interview Questions
- Computer Glossary
- Who is Who

# The speed of light in air is:**(a)** 3 × 10^{8} cm/s **(b)** 3 × 10^{8} mm/s **(c)** 3 × 10^{8} km/s **(d)** 3 × 10^{8} m/s

**(d) 3 × 10 ^{8} m/s**

__Explanation__

The speed of light in vacuum is commonly denoted by 'c'. It is a universal physical constant, with its exact value 299,792,458 m/s (approximately 3,00,000 km/s or 186,000 mi/s).

- Related Articles
- The absolute refractive index of Ruby is 1.7. Find the speed of light in Ruby. The speed of light in a vacuum is 3 × 108 m/s.
- What per cent of \( 108 \mathrm{~km} / \mathrm{h} \) is \( 15 \mathrm{~m} / \mathrm{s} \) ?
- (a) Draw a labelled ray diagram to show the path of a ray of light incident obliquely on one face of a glass slab. (b) Calculate the refractive index of the material of a glass slab. Given that the speed of light through the glass slab is 2 x 108 m/s and in air is 3 x 108 m/s.(c) Calculate the focal length of a lens, if its power is – 2·5 D.
- Finding n-th term of series 3, 13, 42, 108, 235... in C++
- The speed of light in air is $3 × 10^8\ m/s$. In medium X its speed is $2 × 10^8\ m/s$ and in medium Y the speed of light is $2.5 × 10^8\ m/s$. Calculate:(a) $_{air} \mathrm{n}_X$(b) $_{air} \mathrm{n}_Y$(c) $_{x} \mathrm{n}_Y$
- A bus travels 54 km in 90 minutes. The speed of the bus is$(a)$. 0.6 m/s$(b)$. 10 m/s$(c)$. 5.4 m/s$(d)$. 3.6 m/s
- The refractive index of water is \( 1.33 \) and the speed of light in air is $3\times {10}^{8}m{s}^{-1}$. Calculate the speed of light in water.
- A scooterist covers a distance of 3 kilometres in 5 minutes. Calculate his speed in:(a) centimetres per second (cm/s)(b) metres per second (m/s) (c) kilometres per hour (km/h)
- Which of the following could not be a unit of speed(a) $km/h$(b) $s/m$(c) $m/s$(d) $mms^{-1}$
- A bus increases its speed from $36\ km/h$ to $72\ km/h$ in $10\ seconds$. Its acceleration is:(a) $5\ m/s^2$(b) $2\ m/s^2$(c) $3.6\ m/s^2$(d) $1\ m/s^2$
- Find HCF of 24, 36, 108, 192.
- Find LCM of 24, 36, 108, 192
- Which of the following could not be a unit of acceleration?,b>(a) $km/s^2$(b) $cms^{-2}$(c) $km/s$(d) $m/s^2$
- Write the standard form of $\frac{36}{108}$.
- Light enters from air to water having a refractive index 4/3. Find the speed of light in water if the speed of light in vacuum is 3x108m/s.

Advertisements