Questions From the Industry Canada Basic Question Bank

Part C

of A to C

Name three good electrical conductors.

* Gold, silver, aluminum

Name four good electrical insulators.

* Glass, air, plastic, porcelain

The most common material used to make a resistor is:

* carbon

What is the word used to describe how fast electrical energy is used?

* Power

If you have light bulbs marked 40 watts, 60 watts and 100 watts, which one will use electrical energy the fastest?

* The 100 watt bulb

What is the basic unit of electrical power?

* The watt

Which electrical circuit will have no current?

* An open circuit

If a current of 2 amperes flows through a 50-ohm resistor, what is the voltage across the resistor?

* 100 volts

A lamp has a resistance of 30 ohms and a 6 volt battery is connected. The current flow will be:

* 0.2 ampere

Five 10 ohm resistors connected in series equals:

* 50 ohms

Why would a large size resistor be used instead of a smaller one of the same resistance?

* For greater power dissipation

When two 500 ohm 1 watt resistors are connected in parallel, they can dissipate a maximum total power of:

* 2 watts

One advantage of replacing a 50 ohm resistor with a parallel

combination of two similarly rated 100 ohm resistors is that the

parallel combination will have:

* the same resistance but greater power rating

Resistor wattage ratings are:

* determined by heat dissipation qualities

What term means the number of times per second that an alternating

current flows back and forth?

* Frequency

Electrical energy at a frequency of 7125 kHz is in what frequency

range?

* Radio

What is the name for the distance an AC signal travels during one

complete cycle?

* Wavelength

What does 60 hertz (Hz) mean?

* 60 cycles per second

A two-times increase in power results in a change of how many dB?

* 3 dB higher

The unit "decibel" is used to indicate:

* a mathematical ratio

The power output from a transmitter increases from 1 watt to 2 watts.

This is a db increase of:

* 3

If two equal-value capacitors are connected in parallel, what is their total capacitance?

* Twice the value of one capacitor

In inductances, AC may be opposed by both resistance of winding wire and reactance due to inductive effect. The term which includes resistance and reactance is:

* Impedance

A force of repulsion exists between two _________ magnetic poles.

* like

A permanent magnet would most likely be made from:

* steel

A tuned circuit is formed from two basic components. These are:

* inductors and capacitors

How is a voltmeter usually connected to a circuit under test?

* In parallel with the circuit

How is an ammeter usually connected to a circuit under test?

* In series with the circuit

What does a multimeter measure?

* Voltage, current and resistance

In measuring volts and amperes, the connections should be made with:

* the voltmeter in parallel and ammeter in series

What connects your transceiver to your antenna?

* A feed line

What commonly available antenna feed line can be buried directly in the ground for some distance without adverse effects?

* coaxial cable

What is a coaxial cable?

* A center wire inside an insulating material which is covered by a metal sleeve or shield

What is the best antenna feed line to use, if it must be put near grounded metal objects?

* Coaxial cable

What commonly available antenna feed line can be buried directly in the ground for some distance without adverse effects?

* Coaxial cable

When antenna feed lines must be placed near grounded metal objects,which of the following feed lines should be used?

* Coaxial cable

If your transmitter and antenna are 15 metres apart, but are connected by 65 metres of RG-58 coaxial cable, what should be done to reduce feed line loss?

* Shorten the excess cable

As the length of a feed line is changed, what happens to signal loss?

* Signal loss increases as length increases

What does an SWR reading of 1:1 mean?

* The best impedance match has been attained

What does an SWR reading of less than 1.5:1 mean?

* A fairly good impedance match

What kind of SWR reading may mean poor electrical contact between parts

of an antenna system?

* A jumpy reading

An SWR meter measures the degree of match between transmission line and antenna by:

* comparing forward and reflected voltage

What device might allow use of an antenna on a band it was not designed for?

* An antenna tuner

When will a power source deliver maximum output to the load?

* When the impedance of the load is equal to the impedance of the source

What happens when the impedance of an electrical load is equal to the internal impedance of the power source?

* The source delivers maximum power to the load

The reason that an RF transmission line should be matched at the

transmitter end is to:

* transfer the maximum amount of power to the antenna

An isotropic antenna is a:

* hypothetical point source

A dipole antenna will emit a vertically polarized wave if it is:

* mounted vertically

If an electromagnetic wave leaves an antenna vertically polarized, it will arrive at the receiving antenna, by ground wave:

* vertically polarized

If an antenna is made longer, what happens to its resonant frequency?

* It decreases

If an antenna is made shorter, what happens to its resonant frequency?

* It increases

The property of an antenna, which defines the range of frequencies to which it will respond, is called its:

* bandwidth

What is an advantage of downward sloping radials on a ground plane antenna?

* It brings the feed point impedance closer to 50 ohms

Which of the following transmission lines will give the best match to

the base of a quarter-wave ground-plane antenna?

* 50 ohms coaxial cable

The main characteristic of a vertical antenna is that it will:

* receive signals equally well from all compass points around it

How many directly driven elements do most Yagi antennas have?

* One

A dipole transmitting antenna, placed so that the ends are pointing North/South, radiates:

* mostly to the East and West

What is a cubical quad antenna?

* Two or more parallel four- sided wire loops, each approximately one-electrical wavelength long

What is a delta loop antenna?

* A type of cubical quad antenna, except with triangular elements rather than square

What type of propagation usually occurs from one hand- held VHF

transceiver to another nearby?

* Line-of-sight propagation

The radio wave which follows a path from the transmitter to the

ionosphere and back to earth is known correctly as the:

* ionospheric wave

What causes the ionosphere to form?

* Solar radiation ionizing the outer atmosphere

When is the ionosphere most ionized?

* Midday

When is the ionosphere least ionized?

* Shortly before dawn

What is a skip zone?

* An area which is too far away for ground-wave propagation, but too close for sky-wave propagation

Skip zone is:

* a zone between the end of the ground wave and the point where the first refracted wave returns to earth

On the VHF and UHF bands, polarization of the receiving antenna is very important in relation to the transmitting antenna, yet on HF bands it is relatively unimportant. Why is that so?

* The ionosphere can change the polarization of the signal from moment to moment

How do sunspots change the ionization of the atmosphere?

* The more sunspots there are, the greater the ionization

How long is an average sunspot cycle?

* 11 years

All communication frequencies throughout the spectrum are affected in varying degrees by the:

* sun

Propagation cycles have a period of approximately 11:

* years

What happens to signals higher in frequency than the critical

frequency?

* They pass through the ionosphere

What does maximum usable frequency mean?

* The highest frequency signal that will reach its intended

Destination

In the northern hemisphere, in which direction should a directional antenna be pointed to take maximum advantage of auroral propagation?

* North

If you receive a weak, distorted signal from a distance, and close to the maximum usable frequency, what type of propagation is probably occurring?

* Scatter

What is a characteristic of HF scatter signals?

* A wavering sound

What makes HF scatter signals often sound distorted?

* Energy scattered into the skip zone through several radio-wave paths

Why are HF scatter signals usually weak?

* Only a small part of the signal energy is scattered into the skip zone

How can cross-modulation be reduced?

* By installing a suitable filter at the receiver

Stereo amplifiers often have long leads which pick up transmittedsignals because they act as:

* receiving antennas

If someone tells you that signals from your hand-held transceiver are interfering with other signals on a frequency near yours, what may be the cause?

* Your hand-held may be transmitting spurious emissions

If your transmitter sends signals outside the band where it is

transmitting, what is this called?

* Spurious emissions

What is meant by harmonic radiation?

* Unwanted signals at frequencies which are multiples of the

fundamental (chosen) frequency

Why is harmonic radiation from an amateur station not wanted?

* It may cause interference to other stations and may result in out-of-band signals

What type of filter might be connected to an amateur HF transmitter to cut down on harmonic radiation?

* A low pass filter

Why do modern HF transmitters have a built-in low pass filter in their RF output circuits?

* To reduce harmonic radiation