Radio Teacher

Technicians Test Subelement T4

Questions and Answers

**Radio Teacher Home**

**Technician Test**

**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

Amperes

Electrical Power is measured in which of the following units?

Watts

Watts

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

Current

Current

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

A direct current

A direct current

What is the standard unit of frequency?

The Hertz

The Hertz

How much voltage does an automobile battery usually supply?

About 12 volts

About 12 volts

What is the basic unit of resistance?

The ohm

The ohm

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

An alternating current

An alternating current

Which of the following is a good electrical conductor?

Copper

Copper

Which of the following is a good electrical insulator?

Glass

Glass

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

Resistance

Resistance

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

Ammeter

Ammeter

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

Voltmeter

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

Wavelength

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

Frequency

Frequency

What does 60 hertz (Hz) mean?

60 cycles per second

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?

Radio waves

Radio waves

How fast does a radio wave travel through space?

At the speed of light

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

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

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

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

The physical length of the wave

What is the frequency range of the 2 meter band in the United States?

144 to 148 MHz

144 to 148 MHz

What is the frequency range of the 6 meter band in the United States?

50 to 54 MHz

50 to 54 MHz

What is the frequency range of the 70 centimeter band in the United States?

420 to 450 MHz

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?

Receiver

Receiver

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

Transmitter

Transmitter

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

Receiver, transmitter

Receiver, transmitter

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

Power Supply

Power Supply

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

Amplifier

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

Lithium-ion

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

1.2 volts

1.2 volts

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

Carbon-zinc

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.

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

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)

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)

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)

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

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

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

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

1 volt

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

10 volts

10 volts

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

20 volts

20 volts

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

2 amperes

2 amperes

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

10 amperes

10 amperes

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

What unit is used to describe electrical power?

Watt

Watt

What is the formula used to calculate electrical power in a DC circuit?

Power (P) equals voltage (E) multiplied by current (I)

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

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

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

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

10 amperes

How many milliamperes is the same as 1.5 amperes?

1500 milliamperes

1500 milliamperes

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

1500 kHz

1500 kHz

How many volts are equal to one kilovolt?

one thousand volts

one thousand volts

How many volts are equal to one microvolt?

one one-millionth of a volt

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

0.5 watts