1.
The instrument used to measure current is
Correct Answer
C. Ammeter
Explanation
An ammeter is the instrument used to measure current in a circuit. It is specifically designed to measure the flow of electric current in amperes. Unlike a voltmeter, which measures voltage, an ammeter is connected in series with the circuit, allowing the current to pass through it and display the reading directly. An ohmmeter is used to measure resistance, and a power meter is used to measure power consumption. Therefore, the correct instrument to measure current is an ammeter.
2.
The instrument used to measure voltage is
Correct Answer
A. Voltmeter
Explanation
A voltmeter is used to measure the voltage in an electrical circuit. It is specifically designed to measure the potential difference between two points in a circuit. Voltmeters are connected in parallel to the circuit being measured and have a high resistance to avoid drawing significant current from the circuit. This allows them to accurately measure the voltage without affecting the circuit's behavior. Therefore, a voltmeter is the correct instrument to measure voltage.
3.
The instrument used to measure resistance is
Correct Answer
B. Ohmmeter
Explanation
An ohmmeter is used to measure resistance. It is specifically designed to measure the electrical resistance in an electrical circuit. This instrument applies a known voltage to the circuit and measures the resulting current flow. By using Ohm's law (V = IR), the ohmmeter can calculate the resistance based on the voltage and current measurements. Therefore, an ohmmeter is the correct instrument for measuring resistance.
4.
The output power of a transmitter is measured by unit called?
Correct Answer
C. Watts
Explanation
The output power of a transmitter is measured in watts. Watts is the unit of power, which represents the rate at which energy is transferred or used. In the context of a transmitter, the power output is a measure of the energy being transmitted per unit of time. Therefore, watts is the appropriate unit to measure the output power of a transmitter.
5.
Rubber is an example of
Correct Answer
B. Insulator
Explanation
Rubber is a good example of an insulator because it does not conduct electricity. It has high electrical resistance, meaning that it does not allow electric current to flow through it easily. This property makes rubber useful for insulating electrical wires and cables to prevent electrical shocks or short circuits. Additionally, rubber is also stretchable, but its insulating properties are more relevant in this context.
6.
Copper is an example of
Correct Answer
C. Conductor
Explanation
Copper is an example of a conductor because it is a metal that allows the flow of electric current. Conductors have high electrical conductivity, which means they have many free electrons that can move easily within the material when a voltage is applied. Copper is widely used as a conductor in electrical wiring, circuits, and other electrical components due to its excellent conductivity properties.
7.
Silicon is an example of
Correct Answer
B. Semi-conductor
Explanation
Silicon is an example of a semi-conductor because it has properties that allow it to conduct electricity under certain conditions. It is neither a liquid nor a resistor nor a capacitor.
8.
The quantity of 144.474 MHZ refers to
Correct Answer
B. Frequency
Explanation
The quantity of 144.474 MHz refers to the frequency. Frequency is the number of cycles of a periodic wave that occur in a unit of time. In this case, the quantity 144.474 MHz represents the number of cycles that occur in one second. MHz stands for megahertz, which is a unit of frequency equal to one million hertz. Therefore, the correct answer is frequency as it represents the measurement of cycles occurring in a given time period.
9.
The frequency 145.00 MHZ has an approximate wavelength of
Correct Answer
B. 2 meters
Explanation
The frequency of 145.00 MHz corresponds to a wavelength of approximately 2 meters. This can be determined using the equation c = fλ, where c is the speed of light (approximately 3 x 10^8 meters per second), f is the frequency, and λ is the wavelength. Rearranging the equation to solve for λ, we get λ = c/f. Plugging in the values, we find that λ = 3 x 10^8 / 145 x 10^6 = 2.07 meters. Therefore, the approximate wavelength for a frequency of 145.00 MHz is 2 meters.
10.
The frequency band 144 MHZ to 46 MHZ is within the
Correct Answer
C. VHF Band
Explanation
The frequency range mentioned, 144 MHz to 46 MHz, falls within the VHF (Very High Frequency) band. VHF band generally covers the frequency range of 30 MHz to 300 MHz, and is commonly used for various applications including television broadcasting, FM radio, and aviation communication.
11.
The terminal voltage of an ordinary flashlight battery is
Correct Answer
B. 1.5 volts
Explanation
The correct answer is 1.5 volts. This is because most ordinary flashlight batteries, such as AA or AAA batteries, typically have a nominal voltage of 1.5 volts. This voltage is sufficient to power the flashlight and provide the necessary electrical energy for the light to function properly.
12.
One thousand watts is sometimes written as
Correct Answer
A. 1 kilowatt
Explanation
The correct answer is 1 kilowatt because kilo is a prefix that denotes a factor of 1000. In this case, kilo is being used to represent a unit of power, which is watts. Therefore, 1 kilowatt is equivalent to 1000 watts.
13.
Sound waves are also called
Correct Answer
B. Audio frequency waves
Explanation
Sound waves are also known as audio frequency waves because they are the vibrations of air molecules that are within the range of human hearing. These waves have frequencies in the range of 20 Hz to 20,000 Hz, which corresponds to the audible spectrum for humans. Radio frequency waves, spectrum frequency waves, and data frequency waves are not correct terms for sound waves, as they refer to different types of electromagnetic waves used in communication and data transmission.
14.
An open circuit has a resistance of
Correct Answer
D. Infinity
Explanation
An open circuit is a circuit that is not complete, meaning there is a break in the circuit and no current can flow. In this case, there is no path for the current to flow, so the resistance is considered to be infinite. This means that the voltage across the open circuit is theoretically infinite, as there is no current flowing to create a voltage drop across any resistance.
15.
A short circuit has a resistance of
Correct Answer
C. Zero
Explanation
In a short circuit, the current bypasses the normal path and flows directly from the source to the ground without encountering any resistance. This results in a negligible resistance value, practically approaching zero. Therefore, the correct answer is zero.
16.
When current passes through a path of lesser resistance thereby destroying the fuse in a circuit, we say that the circuit is
Correct Answer
C. Short Circuited
Explanation
When current passes through a path of lesser resistance, it creates a shortcut for the current to flow, bypassing the intended components of the circuit. This causes a sudden increase in current, leading to overheating and potentially damaging the circuit. This phenomenon is known as a short circuit.
17.
What is the unit of resistance?
Correct Answer
B. Ohm
Explanation
The unit of resistance is Ohm. Ohm is the standard unit used to measure electrical resistance. It is named after the German physicist Georg Simon Ohm, who formulated Ohm's law. Ohm's law states that the current passing through a conductor is directly proportional to the voltage applied to it and inversely proportional to its resistance. Therefore, resistance is measured in Ohms to quantify the opposition to the flow of electric current in a circuit.
18.
What is the unit of inductance?
Correct Answer
C. Henry
Explanation
The unit of inductance is Henry. Inductance is a property of an electrical circuit that opposes any change in the flow of current. It is measured in Henry, named after the American scientist Joseph Henry. Impedance is a measure of the opposition to the flow of current in an electrical circuit, but it is not the unit of inductance. Joules is the unit of energy, and gamma is not a unit of measurement in this context.
19.
One cycle of a wave is measured in
Correct Answer
D. Hertz
Explanation
The correct answer is Hertz. One cycle of a wave is measured in Hertz, which is the unit of frequency. Hertz represents the number of cycles or oscillations of a wave that occur in one second. Gigahertz, Megahertz, and Kilohertz are also units of frequency, but they represent a higher number of cycles per second. Therefore, Hertz is the most accurate unit to measure one cycle of a wave.
20.
What is the unit of capacitance?
Correct Answer
C. FARAD
Explanation
The unit of capacitance is Farad. Capacitance is a measure of an object's ability to store an electric charge. It is defined as the ratio of the electric charge stored on an object to the potential difference across the object. The Farad is the SI unit for capacitance and is named after the English physicist Michael Faraday.
21.
The prefix PICO means
Correct Answer
C. 10 -12
Explanation
The prefix PICO represents a factor of 10 raised to the power of -12. This means that any unit or value with the prefix PICO is 10^-12 times smaller than the base unit or value. It is commonly used in scientific measurements and represents a very small quantity.
22.
The prefix MEGA means
Correct Answer
A. 10 6
Explanation
The prefix MEGA represents a value of 10^6. This means that any number or unit with the prefix MEGA is equal to one million times the base unit. For example, a megabyte (MB) is equal to 1 million bytes, and a megawatt (MW) is equal to 1 million watts.
23.
The opposition of a conductor to the flow of current is
Correct Answer
B. Resistance
Explanation
Resistance is the correct answer because it refers to the opposition of a conductor to the flow of current. Resistance is a property of a material that hinders the movement of electrons, causing them to collide with atoms and generating heat. It is measured in ohms and is dependent on factors such as the material's length, cross-sectional area, and temperature.
24.
The circuit element that opposes any change in current is
Correct Answer
A. Inductor
Explanation
An inductor is a circuit element that opposes any change in current. When the current through an inductor changes, it creates a back electromotive force (EMF) that opposes the change in current. This property of inductors is due to the phenomenon of electromagnetic induction. In contrast, a conductor allows the flow of current without opposing it, while a reductor and mho are not relevant terms in the context of opposing current flow. Therefore, the correct answer is inductor.
25.
The circuit element that opposes any change in voltage is
Correct Answer
D. Capacitor
Explanation
A capacitor is a circuit element that opposes any change in voltage. When a voltage is applied across a capacitor, it stores electrical energy in the form of an electric field. As a result, when there is a sudden change in voltage, the capacitor resists this change by releasing or absorbing energy from its electric field. This property of a capacitor makes it act as a voltage stabilizer or a filter, opposing any sudden changes in voltage and maintaining a more constant voltage level.
26.
What is the unit of admittance?
Correct Answer
B. Siemens
Explanation
The unit of admittance is Siemens. Admittance is the reciprocal of impedance and measures the ease with which an electrical circuit or device allows the flow of an alternating current. Siemens is the unit of measurement for conductance, which is the real part of admittance. It is named after Ernst Werner von Siemens, a German inventor and industrialist.
27.
What is to be provided in house entrance of circuit switches in order to be sure that radio or other equipment when short-circuited will not cause fire of electric origin?
Correct Answer
B. Fuse
Explanation
In order to ensure that radio or other equipment, when short-circuited, will not cause a fire of electric origin, a fuse should be provided in the house entrance of circuit switches. A fuse is a safety device that is designed to break the circuit and prevent excessive current flow in the event of a short circuit or overload. By melting the fuse wire, it disconnects the circuit and protects the electrical system from overheating and potential fire hazards.
28.
An instrument that measures frequency
Correct Answer
C. Frequency Counter
Explanation
A frequency counter is an instrument that measures the frequency of a signal. It counts the number of cycles of the signal within a specific time period and provides an accurate measurement of the frequency. This instrument is commonly used in various fields such as telecommunications, electronics, and physics to analyze and monitor the frequency of signals. It is different from a frequency spectrum analyzer, which displays the frequency components of a signal in a graphical form.
29.
An instrument used to measure resistance, voltage and currents
Correct Answer
C. Multimeter
Explanation
A multimeter is a versatile instrument that can be used to measure resistance, voltage, and currents. It is designed to provide accurate readings for these electrical parameters. Unlike an oscilloscope, which is primarily used to visualize waveforms, a multimeter is more focused on providing numerical measurements. While a signal generator is used to produce electrical signals, and a power meter is used to measure power consumption, neither of these instruments can measure resistance, voltage, and currents as comprehensively as a multimeter can. Therefore, a multimeter is the most suitable instrument for this purpose.
30.
Connecting a resistor in series with a meter will
Correct Answer
B. Increase the measuring range of a voltmeter
Explanation
Connecting a resistor in series with a meter will increase the measuring range of a voltmeter. This is because adding a resistor in series increases the overall resistance in the circuit, which in turn decreases the current flowing through the meter. As the current decreases, the voltage drop across the meter also decreases, allowing the meter to measure higher voltages without being overloaded. Therefore, the measuring range of the voltmeter is increased.
31.
Connecting a resistor in parallel with a meter will
Correct Answer
A. Increase the measuring range of ammeter
Explanation
Connecting a resistor in parallel with a meter will increase the measuring range of an ammeter. When a resistor is connected in parallel with the meter, it creates an additional path for current to flow. This decreases the overall resistance in the circuit, allowing more current to pass through the ammeter. As a result, the ammeter can measure higher currents that were previously outside its original measuring range.
32.
Two identical resistors are connected in parallel. What is the resultant resistance?
Correct Answer
B. Half the value of one resistor
Explanation
When two identical resistors are connected in parallel, the resultant resistance is half the value of one resistor. This is because in a parallel circuit, the total resistance is inversely proportional to the number of resistors. Since the two resistors are identical, they have the same resistance value. When connected in parallel, the total resistance is divided equally between the two resistors, resulting in half the value of one resistor.
33.
Two identical capacitors are connected in parallel. What is the resultant capacitance?
Correct Answer
C. Twice the value of one capacitor
Explanation
When two identical capacitors are connected in parallel, the total capacitance is equal to the sum of the individual capacitances. Since the capacitors are identical, their capacitance values are the same. Therefore, when they are connected in parallel, the resultant capacitance will be twice the value of one capacitor.
34.
Two identical capacitors are connected in series. What is the total capacitance?
Correct Answer
B. Half the value of one capacitor
Explanation
When capacitors are connected in series, the total capacitance is given by the reciprocal of the sum of the reciprocals of the individual capacitances. Since the two capacitors are identical, their capacitances are the same. Therefore, the reciprocal of the sum of their reciprocals is equal to half of the value of one capacitor.
35.
Audio frequency range is from
Correct Answer
A. 300 HZ to 30 KHZ
Explanation
The correct answer is 300 HZ to 30 KHZ. This is because audio frequencies typically range from the lower frequency of 20 Hz (which is the lower limit of human hearing) to the upper frequency of 20 KHz (which is the upper limit of human hearing). Therefore, the given range of 300 Hz to 30 KHz falls within the range of audible frequencies.
36.
Storage batteries are usually rated in
Correct Answer
B. Ampere-hour
Explanation
Storage batteries are usually rated in Ampere-hour because it is a unit of electrical charge that represents the amount of current a battery can deliver over a period of time. It is a common practice to rate batteries in terms of their capacity to provide a certain amount of current for a specific duration. Ampere-hour is a reliable measure for comparing the energy storage capacity of different batteries and helps in determining their suitability for various applications.
37.
A good measure to prevent the use of the Amateur Radio Station equipment by unauthorized person is
Correct Answer
B. Use of key operated power switch
Explanation
The use of a key-operated power switch is a good measure to prevent the use of Amateur Radio Station equipment by unauthorized individuals. This type of switch requires a key to be inserted and turned in order to activate or deactivate the power supply. By restricting access to the key, only authorized personnel can operate the equipment, reducing the risk of unauthorized use or tampering. This helps ensure the security and integrity of the radio station and its operations.
38.
All antenna system and equipment should be grounded when the station is not in use in order to
Correct Answer
C. Protect the station and building from damage due to nearby lightning strike
Explanation
When the station and equipment are grounded, it helps to protect them from damage caused by nearby lightning strikes. By providing a path for the electrical current to follow, the grounding system can redirect the energy from the lightning strike safely into the ground, preventing it from damaging the station and building. Without proper grounding, the lightning strike could potentially cause severe damage to the station, appliances, and the building itself. Therefore, grounding is essential to safeguard the station and building from the destructive effects of lightning strikes.
39.
What should you do to prevent shock when working on high voltage power supply?
Correct Answer
C. Discharge the filter capacitors
Explanation
To prevent shock when working on a high voltage power supply, it is important to discharge the filter capacitors. This is necessary because capacitors store electrical energy, and if they are not discharged before working on the power supply, they can still hold a charge and pose a risk of electric shock. By discharging the filter capacitors, any stored electrical energy is safely dissipated, reducing the risk of shock when working on the power supply.
40.
Give the name of an instrument that is useful for monitoring relative RF output during transmitter and antenna adjustment
Correct Answer
B. Grid-dip meter
Explanation
A grid-dip meter is a useful instrument for monitoring relative RF output during transmitter and antenna adjustment. It is specifically designed to measure the resonance frequency of an electrical circuit. By measuring the resonance frequency, it can indicate the efficiency of the transmitter and antenna system. This information is crucial for adjusting the equipment to achieve optimal performance. Therefore, a grid-dip meter is an essential tool for monitoring and adjusting RF output in this context.
41.
Ohm's Law is stated in the following formula
Correct Answer
C. V = IR
Explanation
Ohm's Law states that the voltage (V) across a conductor is directly proportional to the current (I) flowing through it, and inversely proportional to the resistance (R) of the conductor. The equation V = IR represents this relationship, where V is the voltage, I is the current, and R is the resistance. This equation is derived from the other equations given, where P = IV represents the power, I = VR represents the current, and R = IV represents the resistance. Therefore, the correct answer is V = IR.
42.
The power formula is
Correct Answer
A. P = I2R
Explanation
The given power formula is P = I^2R, which means that power (P) is equal to the square of the current (I) multiplied by the resistance (R). This formula is derived from Ohm's law, which states that the current flowing through a conductor is directly proportional to the voltage across it and inversely proportional to the resistance. By squaring the current and multiplying it by the resistance, we can calculate the power dissipated in a circuit.
43.
To produce higher output voltage, dry cells should be connected in
Correct Answer
C. Series
Explanation
To produce higher output voltage, dry cells should be connected in series. When dry cells are connected in series, the positive terminal of one cell is connected to the negative terminal of the next cell, creating a cumulative effect. This increases the total voltage output of the cells. In contrast, connecting cells in parallel would increase the total current output but not the voltage.
44.
The larger the diameter of a copper wire
Correct Answer
B. The lower is the resistance of the wire
Explanation
The larger the diameter of a copper wire, the lower is the resistance of the wire. This is because a larger diameter means there is more cross-sectional area for the current to flow through, resulting in less obstruction to the flow of electrons. As a result, there is less resistance to the flow of electric current in a wire with a larger diameter.
45.
The longer the copper wire
Correct Answer
C. The higher is the resistance of the wire
Explanation
The longer the copper wire, the higher is the resistance of the wire. This is because resistance is directly proportional to the length of the wire. As the length increases, the number of collisions between the moving electrons and the atoms in the wire also increases, resulting in a higher resistance.
46.
The longer the copper wire,
Correct Answer
B. The higher is the resistance of the wire
Explanation
The statement "the higher is the resistance of the wire" is the correct answer because the resistance of a wire is directly proportional to its length. This means that as the length of the copper wire increases, the resistance also increases. This relationship is described by Ohm's Law, which states that resistance is equal to the product of the resistivity of the material and the length of the wire, divided by its cross-sectional area. Therefore, the longer the copper wire, the higher its resistance.
47.
The frequency range 144 MHz to 146 MHz is within
Correct Answer
B. VHF band
Explanation
The frequency range 144 MHz to 146 MHz is within the VHF band. VHF stands for Very High Frequency and it refers to the range of electromagnetic waves with frequencies between 30 MHz and 300 MHz. The given frequency range falls within this range, making VHF band the correct answer.
48.
In order to protect the station from lightning, all antenna system and equipment should be
Correct Answer
D. Grounded
Explanation
To protect the station from lightning, all antenna systems and equipment should be grounded. Grounding helps to divert the electrical current from lightning strikes safely into the ground, preventing damage to the equipment and reducing the risk of fire or electrical hazards. By providing a low-resistance path for the electrical energy, grounding ensures that any excess energy is dissipated harmlessly, rather than being transmitted through the equipment. This helps to protect both the station and the personnel working with the equipment from potential damage or injury caused by lightning strikes.
49.
Copper is an example of
Correct Answer
A. Conductor
Explanation
Copper is an example of a conductor because it has a high electrical conductivity. Conductors are materials that allow the flow of electric current with minimal resistance. Copper is commonly used in electrical wiring and other applications where the efficient flow of electricity is required.
50.
In order to protect a personnel and prevent shock, the equipment should be connected good earth ground through the
Correct Answer
C. Cold water pipe
Explanation
To protect personnel and prevent shock, equipment should be connected to a good earth ground. The cold water pipe is a suitable choice for grounding because it is typically made of metal and is in contact with the earth. This provides a low-resistance path for electrical current to flow safely into the ground, reducing the risk of electric shock. The LPG and hot water pipe may not be suitable for grounding purposes.