Q. No.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
A parallel plate capacitor consists of two circular plates each of radius 12 cm and separated by 5.0 mm. The capacitor is being charged by an external source. The charging current is constant and is equal to 0.15 A. The rate of change of the potential difference between the plates will be:
| 1. | \(1.873 \times 10^7 \mathrm{~V} / \mathrm{s}\) |
| 2. | \(1.873 \times 10^8 \mathrm{~V} / \mathrm{s}\) |
| 3. | \(1.873 \times 10^9 \mathrm{~V} / \mathrm{s}\) |
| 4. | \(1.873 \times 10^{10} \mathrm{~V} / \mathrm{s}\) |
A lamp emits monochromatic green light uniformly in all directions. The lamp is 3% efficient in converting electrical power to electromagnetic waves and consumes 100 W of power. The amplitude of the electric field associated with the electromagnetic radiation at a distance of 5 m from the lamp will be:
1. 1.34 V/m
2. 2.68 V/m
3. 4.02 V/m
4. 5.36 V/m
A variable frequency AC source is connected to a capacitor. Then on increasing the frequency:
| 1. | Both conduction current and displacement current will increase |
| 2. | Both conduction current and displacement current will decrease |
| 3. | Conduction current will increase and displacement current will decrease |
| 4. | Conduction current will decrease and displacement current will increase |
Instantaneous displacement current of 2.0 A is set up in the space between two parallel plates of \(1~\mu F\) capacitor. The rate of change in potential difference across the capacitor is:
1.
2.
3.
4. None of these
Which statement is incorrect?
| 1. | Speed of light in free space \(=\frac{1}{\sqrt{\mu_0 \epsilon_0}}\) |
| 2. | Speed of light in the medium \(=\frac{1}{\sqrt{\mu \epsilon}}\) |
| 3. | \(\frac{E_0}{B_0}=c\) |
| 4. | \(\frac{B_0}{E_0}=c\) |
A capacitor is having a capacity of 2 pF. The electric potential across the capacitor is changing with a value of \(10^{12}~\mathrm{V/s}\). The displacement current is:
| 1. | 2 A | 2. | 3 A |
| 3. | 6 A | 4. | 9 A |
| I: | Light can travel in vacuum but sound cannot do so. |
| II: | Light is an electromagnetic wave and sound is a mechanical wave. |
| 1. | Both I and II are true and II is the correct explanation of I. |
| 2. | Both I and II are true but II is not the correct explanation of I. |
| 3. | I is true but II is false. |
| 4. | I is false but II is true. |
If a source is transmitting an electromagnetic wave of frequency , then the wavelength of the electromagnetic wave transmitted from the source will be:
| 1. | 36.6 m | 2. | 40.5 m |
| 3. | 42.3 m | 4. | 50.9 m |
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