Technicians Test Subelement T4

SUBELEMENT T4 – Radio and electronic fundamentals – 5 exam questions – 5 groups

T4A – Names of electrical units, DC and AC, what is a radio signal, conductors and insulators, electrical components - 1 exam question

Electrical current is measured in which of the following units?
Amperes

Electrical Power is measured in which of the following units?
Watts

What is the name for the flow of electrons in an electric circuit?
Current

What is the name of a current that flows only in one direction?
A direct current

What is the standard unit of frequency?
The Hertz

How much voltage does an automobile battery usually supply?

What is the basic unit of resistance?
The ohm

What is the name of a current that reverses direction on a regular basis?
An alternating current

Which of the following is a good electrical conductor?
Copper

Which of the following is a good electrical insulator?
Glass

What is the term used to describe opposition to current flow in ordinary conductors such as wires?
Resistance

What instrument is used to measure the flow of current in an electrical circuit?
Ammeter

What instrument is used to measure Electromotive Force (EMF) between two points such as the poles of a battery?
Voltmeter

T4B – relationship between frequency and wavelength, identification of bands, names of frequency ranges, types of waves – 1 exam question

What is the name for the distance a radio wave travels during one complete cycle?
Wavelength

What term describes the number of times that an alternating current flows back and forth per second?
Frequency

What does 60 hertz (Hz) mean?
60 cycles per second

Electromagnetic waves that oscillate more than 20,000 times per second as they travel through space are generally referred to as what?

How fast does a radio wave travel through space?
At the speed of light

How does the wavelength of a radio wave relate to its frequency?
The wavelength gets shorter as the frequency increases

What is the formula for converting frequency to wavelength in meters?
Wavelength in meters equals 300 divided by frequency in megahertz

What are sound waves in the range between 300 and 3000 Hertz called?
Voice frequencies

What property of a radio wave is often used to identify the different bands amateur radio operators use?
The physical length of the wave

What is the frequency range of the 2 meter band in the United States?
144 to 148 MHz

What is the frequency range of the 6 meter band in the United States?
50 to 54 MHz

What is the frequency range of the 70 centimeter band in the United States?
420 to 450 MHz

T4C - How radio works: receivers, transmitters, transceivers, amplifiers, power supplies, types of batteries, service life – 1 exam question

What is used to convert radio signals into sounds we can hear?

What is used to convert sounds from our voice into radio signals?
Transmitter

What two devices are combined into one unit in a transceiver?

What device is used to convert the alternating current from a wall outlet into low-voltage direct current?
Power Supply

What device is used to increase the output of a 10 watt radio to 100 watts?
Amplifier

Which of the battery types listed below offers the longest life when used with a hand-held radio, assuming each battery is the same physical size?
Lithium-ion

What is the nominal voltage per cell of a fully charged nickel-cadmium battery?
1.2 volts

What battery type on this list is not designed to be re-charged?
Carbon-zinc

What is required to keep rechargeable batteries in good condition and ready for emergencies?
All of these answers are correct:
They must be inspected for physical damage and replaced if necessary.
They should be stored in a cool and dry location.
They must be given a maintenance recharge at least every 6 months.

What is the best way to get the most amount of energy from a battery?
Draw current from the battery at the slowest rate needed

T4D – Ohms law relationships – 1 exam question

What formula is used to calculate current in a circuit?
Current (I) equals voltage (E) divided by resistance (R)

What formula is used to calculate voltage in a circuit?
Voltage (E) equals current (I) multiplied by resistance (R)

What formula is used to calculate resistance in a circuit?
Resistance (R) equals voltage (E) divided by current (I)

What is the resistance of a circuit when a current of 3 amperes flows through a resistor connected to 90 volts?
30 ohms

What is the resistance in a circuit where the applied voltage is 12 volts and the current flow is 1.5 amperes?
8 ohms

What is the current flow in a circuit with an applied voltage of 120 volts and a resistance of 80 ohms?
1.5 amperes

What is the voltage across the resistor if a current of 0.5 amperes flows through a 2 ohm resistor?
1 volt

What is the voltage across the resistor if a current of 1 ampere flows through a 10 ohm resistor?
10 volts

What is the voltage across the resistor if a current of 2 amperes flows through a 10 ohm resistor?
20 volts

What is the current flowing through a 100 ohm resistor connected across 200 volts?
2 amperes

What is the current flowing through a 24 ohm resistor connected across 240 volts?
10 amperes

T4E - Power calculations, units, kilo, mega, milli, micro - 1 exam question

What unit is used to describe electrical power?
Watt

What is the formula used to calculate electrical power in a DC circuit?
Power (P) equals voltage (E) multiplied by current (I)

How much power is represented by a voltage of 13.8 volts DC and a current of 10 amperes?
138 watts

How much power is being used in a circuit when the voltage is 120 volts DC and the current is 2.5 amperes?
300 watts

How can you determine how many watts are being drawn by your transceiver when you are transmitting?
Measure the DC voltage at the transceiver and multiply by the current drawn when you transmit

How many amperes are flowing in a circuit when the applied voltage is 120 volts DC and the load is 1200 watts?
10 amperes

How many milliamperes is the same as 1.5 amperes?
1500 milliamperes

What is another way to specify the frequency of a radio signal that is oscillating at 1,500,000 Hertz?
1500 kHz

How many volts are equal to one kilovolt?
one thousand volts

How many volts are equal to one microvolt?
one one-millionth of a volt

How many watts does a hand-held transceiver put out if the output power is 500 milliwatts?
0.5 watts