# Quiz: Trivia Questions On Electromagnetic Wave!

33 Questions | Total Attempts: 2763  Settings  Think you know everything there is to know about electromagnetic waves? This quiz can help. You should be aware of what ground wave communications are most effective, what ionization is, the greatest range that the ionosphere has on signals, what type of radio waves are responsible for long-distance communications, and an electromagnetic wave consist of, and what is a wavefront. This quiz can assist you in your learning about electromagnetic waves. All the best.

• 1.
Ground-wave communications is most effective in what frequency range?
• A.

300 kHz to 3 MHz

• B.

3 to 30 MHz

• C.

30 to 300 MHz

• D.

above 300 MHz

• 2.
The ionization causes the signal to be
• A.

Diffused

• B.

Absorbed

• C.

refracted

• D.

Reflected

• 3.
The critical frequency at a particular time is 11.6 MHz. What is the MUF for a transmitting station if the required angle of incidence for propagation to a desired destination is 70°?
• A.

12.3 MHz

• B.

33.9 Hz

• C.

33.9 MHz

• D.

12.3 Hz

• 4.
The ionosphere has the greatest effect on signals in what frequency range?
• A.

300 kHz

• B.

3 to 30 MHz

• C.

30 to 300 MHz

• D.

Above 300 MHz

• 5.
The type of radio wave responsible for long-distance communications by multiple skips is the
• A.

ground wave

• B.

direct-wave

• C.

surface wave

• D.

Sky wave

• 6.
Microwave signals propagate by way of the
• A.

direct wave

• B.

Sky wave

• C.

surface wave

• D.

Standing wave

• 7.
Line-of-sight communications is not a factor in which frequency range?
• A.

VHF

• B.

UHF

• C.

HF

• D.

Microwave

• 8.
A microwave-transmitting antenna is 550 ft high. The receiving antenna is 200 ft high. The maximum transmission distance is
• A.

53.2 km

• B.

53.2 ft

• C.

53.2 mi

• D.

53.2 m

• 9.
To increase the transmission distance of a UHF signal, which of the following should be done?
• A.

Increase antenna gain

• B.

Increase antenna height

• C.

Increase transmitter power

• D.

• 10.
_________ is the amount of voltage induced in a wave by an electromagnetic wave.
• A.

• B.

Field strength

• C.

Magnetic induction

• D.

Power density

• 11.
An electromagnetic wave consists of ____________.
• A.

Both electric field and magnetic field

• B.

An electric field only

• C.

A magnetic field only

• D.

Non-magnetic field only

• 12.
If a radio receiver needs 1 nW/m2 of power density to function, how far away from a 1-W point source will it continue to work?
• A.

8.9 km

• B.

8.9 m

• C.

9.8 km

• D.

9.8 m

• 13.
What causes tropospheric ducting of radio waves?
• A.

A very low pressure area

• B.

An aurora to the north

• C.

Lightning between the transmitting and receiving antenna

• D.

A temperature inversion

• 14.
What is a wavefront?
• A.

A voltage pulse in a conductor

• B.

A current pulse in a conductor

• C.

A voltage pulse across a resistor

• D.

A fixed point in an electromagnetic wave

• 15.
A transmitter has a power output of 115 W at a carrier frequency of 525 MHz. It is connected to an antenna with a power gain of 100 . The receiving antenna is 20,000 m away and has a power gain of 10. Calculate the power delivered to the receiver, assuming free-space propagation. Assume also that there are no losses or mismatches in the system.
• A.

595 nW

• B.

595 pW

• C.

56.9 nW

• D.

56.9 W

• 16.
What causes the ionosphere to absorb radio waves?
• A.

The weather below the ionosphere

• B.

The ionization of the D region

• C.

The presence of the ionized cloud in the E region

• D.

The splitting of the E region

• 17.
Which ionospheric region is closest to the Earth?
• A.

A region

• B.

E Region

• C.

D region

• D.

F region

• 18.
What causes the VHF radio waves to be propagated several hundred miles over oceans?
• A.

An overcast of cirriform clouds

• B.

A high pressure zone

• C.

A polar air mass

• D.

• 19.
Microwave and UHF systems have which of the following in common?
• A.

• B.

Both are cheaper than HF radio

• C.

They operate on the same frequency band.

• D.

They are both line-of-sight (LOS) systems.

• 20.
• A.

Uses molecules in the Earth’s troposphere to scatter some radio energy back to Earth

• B.

Has a limited capability for data transmission

• C.

Is not widely used commercially

• D.

All of the above

• 21.
Which of the following are electromagnetic?
• A.

• B.

Light

• C.

Gamma rays

• D.

All of the above

• 22.
Sky wave cannot be “heard”
• A.

Close to the transmitter

• B.

Far from the transmitter

• C.

In the silent zone

• D.

In the skip zone

• 23.
What power must a point-source of radio waves transmit so that the power density at 3000 meters from the source is 1 µW/m2?
• A.

113 kW

• B.

113 W

• C.

131 W

• D.

131 kW

• 24.
Helical antennas are often used for satellite tracking at VHF because of
• A.

Troposcatter

• B.

Ionospheric refraction

• C.

Subrefraction

• D.

• 25.
Diffraction of electromagnetic waves
• A.

is caused by reflections from the ground wave

• B.

arrives only with spherical wavefronts

• C.

Will occur around edge of a sharp obstacle

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