Electromagnetic Waves Chapter-Wise Test 13

Correct answer Carries: 4.

Wrong Answer Carries: -1.

What does the introduction of displacement current by Maxwell explain about electromagnetic phenomena?

The document explains that displacement current explains the generation of magnetic fields by time-varying electric fields, crucial for the propagation of electromagnetic waves and consistency in Ampere's law.

Generation of magnetic fields by changing electric fields
Elimination of magnetic fields
Generation of static electric fields
Conduction current in vacuums
1

What type of electromagnetic waves were produced and observed by Jagdish Chandra Bose in his experiments?

The document mentions that J.C. Bose produced and observed electromagnetic waves with wavelengths of \( 25 \, \text{mm} \) to \( 5 \, \text{mm} \), which fall in the microwave range.

Microwaves
Radio waves
Infrared waves
Visible light
1

What is the approximate frequency range of microwaves used in radar systems?

The document states that microwaves are in the gigahertz (GHz) range, typically used for radar systems.

\( 500 \, \text{kHz} \) to \( 1000 \, \text{MHz} \)
Gigahertz (GHz) range
\( 4 \times 10^{14} \, \text{Hz} \) to \( 7 \times 10^{14} \, \text{Hz} \)
\( 10^{16} \, \text{Hz} \) and above
2

Why are infrared waves used in thermal imaging devices?

Infrared waves are emitted by objects proportionate to their temperature, allowing thermal imaging devices to detect and map these emissions as temperature variations.

Their high frequency
Their visible spectrum
Their low energy
Their temperature relation
4

Which frequency range corresponds to the AM radio band as per the document?

The document states that the AM radio band ranges from \( 530 \, \text{kHz} \) to \( 1710 \, \text{kHz} \).

\( 88 \, \text{MHz} \) to \( 108 \, \text{MHz} \)
\( 54 \, \text{MHz} \) to \( 890 \, \text{MHz} \)
\( 530 \, \text{kHz} \) to \( 1710 \, \text{kHz} \)
\( 500 \, \text{kHz} \) to \( 1000 \, \text{MHz} \)
3

What is the approximate wavelength range of visible light according to the document?

The document states that visible light ranges from about \( 700 \, \text{nm} \) to \( 400 \, \text{nm} \).

\( 1 \, \text{mm} \) to \( 700 \, \text{nm} \)
\( 400 \, \text{nm} \) to \( 0.6 \, \text{nm} \)
\( 10^{-10} \, \text{m} \) to \( 10^{-14} \, \text{m} \)
\( 700 \, \text{nm} \) to \( 400 \, \text{nm} \)
4

What is the primary source of ultraviolet radiation mentioned in the document?

The document states that the sun is an important source of ultraviolet light, though much of it is absorbed by the ozone layer.

Hot bodies
Special vacuum tubes
The sun
Nuclear reactions
3

Why does the concept of displacement current become essential in understanding electromagnetic wave propagation in free space?

Displacement current accounts for the magnetic field generated by a changing electric field in regions where no conduction current exists, such as in free space, enabling the continuous propagation of electromagnetic waves.

It explains magnetic fields in free space
It eliminates the need for electric fields
It ensures static field propagation
It cancels out conduction currents
1

Why are radio waves used in GPS systems?

Radio waves can travel long distances through the atmosphere and are less affected by weather, allowing satellites to transmit precise timing signals for GPS positioning.

High frequency
Visible emission
Thermal effects
Long-distance travel
4

Gamma rays are produced by which of the following processes?

Gamma rays are produced in nuclear reactions and emitted by radioactive nuclei, as per the document.

Vibration of atoms
Radioactive decay of the nucleus
Acceleration of electrons in aerials
Inner shell electron transitions
2

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