1.
The attraction or repulsion between two electrically charged objects is called
Correct Answer
B. Electrostatic force.
Explanation
The correct answer is electrostatic force. This is because the attraction or repulsion between two electrically charged objects is a result of the electrostatic force. This force is caused by the interaction of the electric charges on the objects and can be either attractive or repulsive depending on the charges involved. It is responsible for phenomena such as the attraction of opposite charges and the repulsion of like charges.
2.
The change in the direction of a compass needle, when a current-carrying wire is brought
near, is called
Correct Answer
A. Electromagnetic deflection.
Explanation
When a current-carrying wire is brought near a compass needle, the magnetic field produced by the wire interacts with the magnetic field of the needle, causing the needle to change its direction. This phenomenon is known as electromagnetic deflection. It is not electrostatic force because electrostatic force is the force between electrically charged objects. It is not magnetic force because magnetic force refers to the force exerted by a magnetic field on a moving charged particle. It is not electroscopic force as there is no such term in physics.
3.
Suppose a certain current in a galvanometer causes the compass needle to deflect by 20
degrees, and then this current is doubled while the polarity stays the same. The angle of the needle deflection will
Correct Answer
C. Increase.
Explanation
When the current in a galvanometer is doubled while the polarity stays the same, the magnetic field produced by the current also doubles. This increased magnetic field will exert a stronger force on the compass needle, causing it to deflect further. Therefore, the angle of the needle deflection will increase.
4.
One important advantage of an electrostatic meter is the fact that
Correct Answer
C. It can detect and indicate ac voltages as well as dc voltages.
Explanation
An electrostatic meter is able to detect and indicate both AC (alternating current) and DC (direct current) voltages. This is an important advantage because it allows the meter to be used in a wide range of applications, whether it be measuring the voltage in a household electrical outlet or analyzing the voltage output of an electronic device. Being able to handle both types of voltages makes the electrostatic meter versatile and useful in various electrical and electronic systems.
5.
A thermocouple
Correct Answer
A. Gets warm when dc flows through it.
Explanation
A thermocouple is a device that consists of two different metals joined together. When a direct current (dc) flows through the thermocouple, it causes a temperature difference between the two junctions of the metals. This temperature difference results in the thermocouple getting warm. Therefore, the correct answer is "gets warm when dc flows through it."
6.
An important advantage of an electromagnet-type meter over a permanent-magnet meter is
the fact that
Correct Answer
D. The electromagnet meter is more rugged.
Explanation
The electromagnet meter is more rugged because it is designed to withstand harsh conditions and is less likely to be damaged or affected by external factors. This makes it more durable and reliable compared to a permanent-magnet meter, which may be more sensitive and prone to damage.
7.
Ammeter shunts are useful because
Correct Answer
C. They allow for measurement of large currents.
Explanation
Ammeter shunts are used to measure large currents because they provide a low resistance path for the current to bypass the majority of it away from the meter movement. This allows the meter to measure only a small fraction of the total current, making it possible to accurately measure large currents without damaging the meter.
8.
Voltmeters should generally have
Correct Answer
A. High internal resistance.
Explanation
Voltmeters should generally have high internal resistance because they are used to measure voltage across a circuit component. If the voltmeter has low internal resistance, it will draw a significant amount of current from the circuit, which will alter the voltage being measured. By having high internal resistance, the voltmeter minimizes the amount of current it draws from the circuit, ensuring accurate voltage measurements. Additionally, high internal resistance allows the voltmeter to have a greater range and sensitivity, making it more versatile in measuring different voltage levels.
9.
In order to measure the power-supply voltage that is applied to an electrical circuit, a voltmeter should be placed
Correct Answer
D. In parallel with the circuit that works from the supply.
Explanation
A voltmeter is used to measure the voltage across a circuit, which is the potential difference between two points. To measure the power-supply voltage, the voltmeter should be connected in parallel with the circuit that is being powered by the supply. This is because in a parallel connection, the voltage across each component is the same, so the voltmeter will measure the same voltage as the circuit. Placing the voltmeter in series with the circuit would disrupt the circuit and affect the voltage measurement.
10.
Which of the following will not normally cause a large error in an ohmmeter reading?
Correct Answer
C. A small change in the resistance to be measured
Explanation
A small change in the resistance to be measured will not normally cause a large error in an ohmmeter reading. This is because ohmmeters are designed to measure resistance and are typically accurate within a certain range. Therefore, a small change in the resistance being measured will not significantly affect the accuracy of the reading.
11.
The main advantage of a FETVM over a conventional voltmeter is the fact that the FETVM
Correct Answer
B. Draws less current from the circuit under test.
Explanation
A FETVM (Field-Effect Transistor Voltmeter) has the main advantage of drawing less current from the circuit under test compared to a conventional voltmeter. This is beneficial because it minimizes the potential impact on the circuit being measured, reducing the chances of altering the voltage levels and affecting the accuracy of the measurement. By drawing less current, the FETVM ensures that the circuit's voltage remains as undisturbed as possible, allowing for more precise and reliable voltage measurements.
12.
Which of the following is not a function of a fuse?
Correct Answer
A. To ensure there is enough current available for an appliance to work right
Explanation
The correct answer is "To ensure there is enough current available for an appliance to work right." This is because a fuse is designed to protect electrical circuits and appliances from excessive current. It works by breaking the circuit when the current exceeds a certain limit, thus preventing damage to the appliance or circuit. Therefore, it does not ensure that there is enough current available for the appliance to work properly.
13.
A utility meter’s motor speed depends directly on
Correct Answer
C. The number of watts being used at the time.
Explanation
The correct answer is the number of watts being used at the time. This is because watts measure the rate at which electrical energy is being consumed. The utility meter's motor speed would directly depend on the number of watts being used, as it would need to accurately measure and record the energy consumption. Ampere-hours, watt-hours, and kilowatt-hours are all measures of energy, but they do not directly determine the motor speed of the utility meter.
14.
A utility meter’s readout indicates
Correct Answer
D. Energy.
Explanation
The readout of a utility meter typically indicates the amount of energy consumed. This is usually measured in kilowatt-hours (kWh) and is used to calculate the cost of electricity consumed by a household or business. Voltage, power, and current are related to energy consumption, but they do not directly indicate the amount of energy consumed. Voltage is the electrical potential difference, power is the rate at which energy is consumed or produced, and current is the flow of electric charge.
15.
A typical frequency counter
Correct Answer
B. Is accurate to six digits or more.
Explanation
The correct answer is "is accurate to six digits or more." This means that a typical frequency counter is able to measure frequencies with a high level of precision. It can provide a reading that is accurate up to six decimal places or more, allowing for very precise measurements of frequency.
16.
A VU meter is never used to get a general indication of
Correct Answer
D. Visible light intensity.
Explanation
A VU meter is a device used to measure and display the intensity of an audio signal. It is commonly used in audio equipment to provide a visual representation of sound levels. However, it is not designed or used to measure or indicate the intensity of visible light. Therefore, the correct answer is visible light intensity.
17.
The meter movement in an illumination meter directly measures
Correct Answer
A. Current.
Explanation
The meter movement in an illumination meter directly measures current. This means that the meter is designed to directly indicate the amount of electric current flowing through it. It is not measuring voltage, power, or energy, but specifically current.
18.
An oscilloscope cannot be used to indicate
Correct Answer
C. Energy.
Explanation
An oscilloscope is a device used to measure and display electrical waveforms. It can indicate the frequency of a waveform by measuring the time period between successive peaks. It can also display the wave shape, showing whether it is a sine wave, square wave, etc. Additionally, it can measure the peak signal voltage, which is the maximum voltage of the waveform. However, an oscilloscope is not designed to measure the energy of a waveform. Energy measurements typically require specialized equipment such as power analyzers.