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Technicians Test Subelement T4
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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?
About 12 volts
 
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?
Radio waves
 
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?
Receiver
 
What is used to convert sounds from our voice into radio signals?
Transmitter
 
What two devices are combined into one unit in a transceiver?
Receiver, transmitter
 
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