The electric and magnetic field of an electromagnetic wave are :

1. in phase and parallel to each other

2. in opposite phase and perpendicular to each other

3. in opposite phasde and parallel to each other

4. in phase and perpendicular to each other

Which one of the following statements is true?

1. Both light and sound waves in air are transverse

2. The sound waves in air are longitudinal while the light waves are transverse

3. Both light and sound waves in air are longitudinal

4. Both light and sound waves can travel in a vacuum

For a transparent medium, relative permeability and permittivity, ${\mu }_r$ $and$ ${\epsilon }_r$ are 1.0 and 1.44 respectively. The velocity of light in this medium would be:

1. 2.5$\times {10}^8$ m/s

2. 3 $\times {10}^8$ m/s

3. 2.08 $\times {10}^8$ m/s

4. 4.32 $\times {10}^8$ m/s

A 100 $\Omega$resistance and a capacitor of 100 $\Omega$ reactance are connected in series across a 220 V source. When the capacitor is 50% charged, the peak value of the displacement current is:

1.  2.2 A

2.  11 A

3.  4.4 A

4.  11$\sqrt{2}$ A

The electric and the magnetic fields, associated with an electromagnetic wave, propagating along the +z-axis, can be represented by:

1.  $\left[\mathrm{E}={\mathrm{E}}_0 \hat{\mathrm{k}}, \mathrm{B}={\mathrm{B}}_0 \hat{\mathrm{i}}\right]$

2.  $\left[\mathrm{E}={\mathrm{E}}_0 \hat{\mathrm{j}}, \mathrm{B}={\mathrm{B}}_0 \hat{\mathrm{j}}\right]$

3.  $\left[\mathrm{E}={\mathrm{E}}_0 \hat{\mathrm{j}}, \mathrm{B}={\mathrm{B}}_0 \hat{\mathrm{k}}\right]$

4.  $\left[\mathrm{E}={\mathrm{E}}_0 \hat{\mathrm{i}}, \mathrm{B}={\mathrm{B}}_0 \hat{\mathrm{j}}\right]$

The dimension of $\frac{1}{2}{\epsilon }_0{E}^2$ where ${\epsilon }_0$ is the permittivity of free space and E is the electric field, is

1. [ML²T^-2]

2. [ML^-1T^-2]

3.  [ML²T^-1]

4.  [MLT^-1]

The intensity of visible radiation at a distance of 1 m from a bulb of 100 W which converts only 5% its power into light is :

(1) 0.4 $W/m^2$             (2) 0.5 $W/m^2$

(3) 0.1 $W/m^2$             (4) 0.01 $W/m^2$

The magnetic field in a plane EM wave traveling in the positive x-direction is given by 

$B=\left(100\mu T\right)\sin \left[\right(2\times {10}^{15}{s}^{-1}\left)\right(t-x/c\left)\right]\hat{j}$

The equation for electric field is :

(1) E=100sin [(2$\times {10}^{15}{s}^{-1})$(t-x/c)]$\left(-\hat{k}\right)$

(2) E=3$\times {10}^{10}$sin [(2$\times {10}^{15}{s}^{-1})$(t-x/c)]$\left(-\hat{k}\right)$

(3) E=3$\times {10}^{10}$sin [(2$\times {10}^{15}{s}^{-1})$(t-x/c)] $\hat{k}$

(4) E=100sin [(2$\times {10}^{15}{s}^{-1})$(t-x/c)] $\hat{k}$