Electromagnetic Wave | MCQs

Explanation

Explanation

In a vacuum or free space, there are no particles or matter, so:

• Pressure (p) is zero.
• Current density (J) is also zero, since there are no charged particles to carry current.

Therefore, the correct observation is p = 0, J = 0.

Explanation

Explanation

Polarization is a property of transverse waves, where the direction of vibration can be oriented in various directions.

Ultrasonic waves are longitudinal waves and cannot be polarized.

Explanation

Gamma (γ) radiation consists of high-energy electromagnetic waves, such as X-rays or gamma rays, that travel in a straight line and are not affected by electric or magnetic fields.

Gamma radiation is a form of ionizing radiation and can travel several meters in air or several centimeters in dense materials before being absorbed.

Explanation

The signal from a remote control to the device operated by it travels at the speed of Light. 

Explanation

Light waves are electromagnetic waves that can travel through a vacuum without a medium.

They consist of oscillating electric and magnetic fields perpendicular to each other and the direction of propagation.

Explanation

Very high frequency is the ITU designation for the range of radio frequency electromagnetic waves from 30 to 300 megahertz,

with corresponding wavelengths of ten to one meter.

ND17-7-2023

Explanation

AM (Amplitude Modulation) radio operates in the frequency range of 550 to 1700 KHz.

Explanation

The propagation of radio signals is greatly influenced by the ionosphere.

Radio propagation is the behavior of radio waves as they travel, or are propagated, from one point to another in a vacuum, or into various parts of the atmosphere.

Propagation of these high-frequency waves over short distances is therefore strongly influenced by

the buildings, trees, and terrain in the vicinity of, and between, the transmitter and receiver.

SH2-8-2023