Electric Field vs Magnetic Field

Q. Maximum value of electric field at a point at a distance of 2 m from the light source of power 60 watt is

1. $50N/C$
2. $30N/C$
3. $2\times {10}^{-3}N/C$
4. $5\times {10}^{-3}N/C$

Q. A radio wave has a maximum magnetic field induction of ${10}^{-4}$T on arrival at a receiving antenna. The maximum electric field intensity of such a wave is

1. zero
2. $3\times {10}^{4}V{m}^{-1}$
3. $5.8\times {10}^4$T
4. $3.0\times {10}^5$T

Q. Which of the given relations is correct?
$(c$ is speed of light, $E$ is electric field strength and $B$ is magnetic field strength$)$

1. $c=2BE$
2. $c=BE$
3. $E=Bc$
4. $B=cE$

Q. A light beam travelling in the X-direction is described by the electric field $E_y=\left(300\text{V/m}\right)\sin \omega (t-x/c).$ An electron is constrained to move along the Y-direction with a speed of $2.0\times {10}^7\text{m/s}.$ Find the maximum electric force and the maximum magnetic force on the electron respectively.

1. $4.8\times {10}^{-17}\text{N},3.2\times {10}^{-18}\text{N}$
2. $9.6\times {10}^{-17}\text{N},6.4\times {10}^{-18}\text{N}$
3. $2.4\times {10}^{-17}\text{N},1.6\times {10}^{-18}\text{N}$
4. $3.6\times {10}^{-17}\text{N},2.5\times {10}^{-18}\text{N}$

Q. A laser beam has intensity $I$. What is the amplitude of electric field in the beam?

1. $\sqrt{\frac{I}{{\epsilon }_{0}C}}$
2. $\sqrt{\frac{2I}{{\epsilon }_{0}C}}$
3. $\sqrt{\frac{3I}{{\epsilon }_{0}C}}$
4. $\sqrt{\frac{4I}{{\epsilon }_{0}C}}$

Q. A light beam travelling in the x-direction is described by the electric field $E_y=300V{m}^{-1}sin\omega (t-\frac{x}{c})$. An electron is constrained to move along the y-direction with a speed of $2.0\times {10}^{7}m{s}^{-1}$. Find the maximum electric force and the maximum magnetic force on the electron.

1. $F_E=4.8\times {10}^{-17}N$ and $F_B=3.2\times {10}^{-18}N$
2. $F_E=8.4\times {10}^{-18}N$ and $F_B=3.2\times {10}^{-18}N$
3. $F_E=3.2\times {10}^{-17}N$ and $F_B=4.8\times {10}^{-18}N$
4. $F_E=4.8\times {10}^{-17}N$ and $F_B=6.4\times {10}^{-17}N$

Q. Suppose that the electromagnetic wave in vacuum is
$\overrightarrow{E}=\{\left(3.1\frac{N}{C}\right)\cos \left[(1.8\frac{rad}{m}\right)y+(5.4\times {10}^6\frac{rad}{s})t]\hat{i}$
What is the frequency?

1. $8.6\times {10}^{5}Hz$
2. $4.3\times {10}^{5}Hz$
3. $8.6\times {10}^{3}Hz$
4. $4.3\times {10}^{3}Hz$

Q. An electromagnetic wave going through vacuum is described by $E=E_0\sin (kx-\omega t)$. Which of the following is/are independent of the wavelength?

1. $k$
2. $\omega$
3. $k\omega$
4. $\frac{k}{\omega }$