In a plane E.M. wave, the electric field oscillates sinusoidally at a frequency of 2.5 Hz and amplitude 480 V/m. The amplitude of the oscillating magnetic field will be:
1.
2.
3.
4.
The energy density of the electromagnetic wave in vacuum is given by the relation:
1.
2.
3.
4.
A lamp radiates power uniformly in all directions. The amplitude of electric field strength at a distance r from it is:
1.
2.
3.
4.
The intensity of visible radiation at a distance of 1 m from a bulb of 100 W which converts only 5% of its power into light, is:
1. 0.4 W/m2
2. 0.5 W/m2
3. 0.1 W/m2
4. 0.01 W/m2
Which of the following statements about electromagnetic waves is/are correct:
A. | X-rays in vacuum travel faster than light waves in vacuum. |
B. | The energy of an X-ray photon is greater than that of a light photon. |
C. | Light can be polarised but X-ray cannot. |
1. A and B
2. B and C
3. A, B and C
4. B only
Which of the following is
not Maxwell's equation?
(= volume charge density, J = current density, m = pole strength, V = volume, S is closed surface, and C is closed loop)
1. | \(\oint_s \vec{E} \cdot \overrightarrow{d S}=\frac{1}{\varepsilon_0} \int_v \rho d V\) |
2. | \(\oint_s \vec{B} \cdot \overrightarrow{d S}=\frac{m}{\mu_0}\) |
3. | \(\oint_s \vec{E} \cdot \overrightarrow{d l}=-\frac{d}{d t} \int_s \vec{B} \cdot \overrightarrow{d S}\) |
4. | \(\oint_s \vec{H} \cdot \overrightarrow{d S}=\int_c\left(\vec{J}+\frac{d}{d t}\left(\varepsilon_0 \vec{E}\right)\right) \cdot \overrightarrow{d S}\) |
The S.I. unit of displacement current is:
1. Henry
2. Coulomb
3. Ampere
4. Farad
If an electromagnetic wave going through a medium is given by;
\(E=E_{0}sin\left ( kx-\omega t \right )\) and \(B=B_{0}sin\left ( kx-\omega t \right ),\) then:
1. | |
2. | If the electric field is in the z-direction then the magnetic field should be in the -y direction |
3. | Both 1 and 2 are correct |
4. | Only 1 is correct |
Consider an electric charge oscillating with a frequency of 10 MHz. The radiation emitted will have a wavelength equal to:
1. | 20 m | 2. | 30 m |
3. | 40 m | 4. | 10 m |
Which of the following electromagnetic waves has minimum frequency?
1. Radio waves
2. Infrared waves
3. Microwaves
4. X-rays