Light is an electromagnetic wave. Its speed in vacuum is given by the expression
Light is an electromagnetic wave. Its speed in vacuum is given by the expression
- [AIIMS 2002]
- A
$\sqrt {{\mu _o}{\varepsilon _o}} $
- B
$\sqrt {\frac{{{\mu _o}}}{{{\varepsilon _o}}}} $
- C
$\sqrt {\frac{{{\varepsilon _o}}}{{{\mu _o}}}} $
- D
$\frac{1}{{\sqrt {{\mu _o}{\varepsilon _o}} }}$
Similar Questions
The electric field in an electromagnetic wave is given by $\overrightarrow{\mathrm{E}}=\hat{\mathrm{i}} 40 \cos \omega\left(\mathrm{t}-\frac{\mathrm{z}}{\mathrm{c}}\right) N \mathrm{NC}^{-1}$. The magnetic field induction of this wave is (in SI unit):
The electric field in an electromagnetic wave is given by $\overrightarrow{\mathrm{E}}=\hat{\mathrm{i}} 40 \cos \omega\left(\mathrm{t}-\frac{\mathrm{z}}{\mathrm{c}}\right) N \mathrm{NC}^{-1}$. The magnetic field induction of this wave is (in SI unit):
- [JEE MAIN 2024]
Calculate the electric and magnetic fields produced by the radiation coming from a $100\; W$ bulb at a distance of $3\; m$. Assume that the efficiency of the bulb is $2.5 \%$ and it is a point source.
Calculate the electric and magnetic fields produced by the radiation coming from a $100\; W$ bulb at a distance of $3\; m$. Assume that the efficiency of the bulb is $2.5 \%$ and it is a point source.
A plane electromagnetic wave, has frequency of $2.0 \times 10^{10}\, Hz$ and its energy density is $1.02 \times 10^{-8}\, J / m ^{3}$ in vacuum. The amplitude of the magnetic field of the wave is close to$....nT$
$\left(\frac{1}{4 \pi \varepsilon_{0}}=9 \times 10^{\circ} \frac{ Nm ^{2}}{ C ^{2}}\right.$ and speed of $1 ight$ $\left.=3 \times 10^{8}\, ms ^{-1}\right)$
A plane electromagnetic wave, has frequency of $2.0 \times 10^{10}\, Hz$ and its energy density is $1.02 \times 10^{-8}\, J / m ^{3}$ in vacuum. The amplitude of the magnetic field of the wave is close to$....nT$
$\left(\frac{1}{4 \pi \varepsilon_{0}}=9 \times 10^{\circ} \frac{ Nm ^{2}}{ C ^{2}}\right.$ and speed of $1 ight$ $\left.=3 \times 10^{8}\, ms ^{-1}\right)$
- [JEE MAIN 2020]
Given below are two statements:
Statement $I$: Electromagnetic waves carry energy as they travel through space and this energy is equally shared by the electric and magnetic fields.
Statement $II$: When electromagnetic waves strike a surface, a pressure is exerted on the surface.In the light of the above statements, choose the most appropriate answer from the options given below:
Given below are two statements:
Statement $I$: Electromagnetic waves carry energy as they travel through space and this energy is equally shared by the electric and magnetic fields.
Statement $II$: When electromagnetic waves strike a surface, a pressure is exerted on the surface.In the light of the above statements, choose the most appropriate answer from the options given below:
- [JEE MAIN 2024]
About $5 \%$ of the power of a $100\; W$ light bulb is converted to visible radiation. What is the average intensity of visible radiation
$(a)$ at a distance of $1 \;m$ from the bulb?
$(b)$ at a distance of $10\; m ?$ Assume that the radiation is emitted isotropically and neglect reflection.
About $5 \%$ of the power of a $100\; W$ light bulb is converted to visible radiation. What is the average intensity of visible radiation
$(a)$ at a distance of $1 \;m$ from the bulb?
$(b)$ at a distance of $10\; m ?$ Assume that the radiation is emitted isotropically and neglect reflection.