Gibilisco: Measuring Devices Quiz Questions And Answers

An oscilloscope is a device used to measure and display electrical waveforms. It can indicate various parameters such as frequency, wave shape, and peak signal voltage. However, it cannot directly measure or indicate energy. Energy is a measure of the amount of work done or power consumed by a system, and it requires additional equipment or calculations to determine. Therefore, an oscilloscope cannot be used to indicate energy.

The force between two electrically charged objects is called electrostatic force. This force is exerted between charged particles and is responsible for the attraction or repulsion between them. It is a fundamental force of nature that plays a crucial role in various phenomena, such as the behavior of electric charges, the formation of electric fields, and the movement of electrons in circuits. Electrostatic force is distinct from other forces like electromagnetic deflection, magnetic force, and electroscopic force, which have different properties and origins.

When the current in a galvanometer is doubled, it means that there is now a stronger current flowing through the galvanometer. As a result, the magnetic field generated by the current is also stronger. This stronger magnetic field will exert a greater force on the needle of the galvanometer, causing it to deflect further. Therefore, the needle deflection will increase when the current is doubled.

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A thermocouple gets warm when current flows through it because it is made of two different metals that are joined together at two junctions. When a current flows through the thermocouple, a temperature difference is created between the two junctions. This temperature difference generates a voltage, known as the Seebeck voltage, which is proportional to the temperature difference. As a result, the thermocouple gets warm when current flows through it.

When a current-carrying wire is brought near a compass needle, the needle deflects or changes its direction. This phenomenon is known as electromagnetic deflection. It occurs due to the interaction between the magnetic field produced by the current in the wire and the magnetic field of the compass needle. The magnetic field around the wire exerts a force on the needle, causing it to move and align itself with the magnetic field of the wire. Therefore, the correct answer is electromagnetic deflection.

The ohmmeter in Fig. 3-17 shows a reading of about 33,000 Ω. This means that the resistance being measured is approximately 33,000 ohms.

Voltmeters should generally have a large internal resistance because they are used to measure voltage in a circuit without affecting the circuit's behavior. A voltmeter with a large internal resistance will draw very little current from the circuit, minimizing the voltage drop across the voltmeter and ensuring accurate measurements. Additionally, a large internal resistance allows the voltmeter to have a high input impedance, which means it will not load the circuit and alter the voltage being measured.

The electromagnet meter is more rugged because it is designed to withstand harsh environments and heavy usage. It is built with durable materials and construction to ensure it can withstand physical impacts and resist damage. This makes it more reliable and long-lasting compared to a permanent-magnet meter, which may be more fragile and prone to damage.

A small change in the resistance to be measured will not cause a major error in an ohmmeter reading because ohmmeters are designed to measure resistance accurately, regardless of small changes in the resistance being measured. The internal circuitry of an ohmmeter is designed to compensate for variations in resistance values, ensuring that the reading remains accurate. Therefore, even if there is a small change in the resistance being measured, the ohmmeter will still provide a reliable reading.

An ammeter shunt is a device that is connected in parallel with the ammeter to divert a portion of the current away from the meter. This allows the ammeter to measure a wide range of currents by adjusting the shunt resistance. Without the shunt, the ammeter would only be able to measure a limited range of currents. Therefore, the use of an ammeter shunt allows for the measurement of a wide range of currents.

A typical frequency counter is usually accurate to six digits or more. This means that it can measure and display frequency values with a high level of precision. The accuracy of a frequency counter is important in various applications where precise frequency measurements are required, such as in scientific research, telecommunications, and electronics. The ability to accurately measure frequency with six or more digits allows for more precise analysis and comparison of signals or waveforms.

A fuse is a safety device that is designed to protect electrical circuits from excessive current. It works by melting and breaking the circuit when the current exceeds a certain limit. The purpose of a fuse is to limit the amount of power that a circuit can deliver and ensure that the current is within safe limits. It also prevents the use of appliances that are too large for a given circuit, as it will blow the fuse if the current exceeds the rated capacity. However, ensuring that there is enough current available for an appliance to work right is not a function of a fuse.

The display in Fig. 3-18 could be caused by a voltage of 6.6 V. This is because the meter is showing a specific value on the display, indicating that it is functioning properly. Therefore, the voltage must be 6.6 V and not any of the other given options.

A VU meter is never used for the measurement of energy because it is specifically designed to measure the volume or level of an audio signal. Energy is a different physical quantity that is typically measured using devices such as wattmeters or kilowatt-hour meters.

The meter movement in an illumination meter measures current. This means that it is designed to measure the flow of electric current in a circuit. The meter movement is calibrated to provide a reading of the current passing through the circuit, allowing users to determine the current level and make appropriate adjustments if needed. This measurement is important in illuminance meters as it helps in evaluating the brightness or intensity of the light source being measured.

An electrostatic meter can detect AC voltages because it is designed to measure the electric field strength, which can vary in both magnitude and direction in an AC circuit. This makes it a useful tool for detecting and measuring alternating currents.

A FETVM (Field Effect Transistor Voltmeter) draws less current from the circuit under test compared to a conventional voltmeter. This is advantageous because it minimizes the impact on the circuit being measured, preventing any significant disruption or loading. By drawing less current, the FETVM ensures accurate voltage measurements without affecting the circuit's performance or accuracy.

The readout of a utility meter indicates the amount of energy consumed. This is typically measured in kilowatt-hours (kWh) and is used to calculate the cost of electricity usage. Voltage, power, and current are all related to energy consumption, but they are not the direct measurement of energy. 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. Therefore, the correct answer is energy.

The motor speed of a utility meter is directly determined by the number of watts being used at the time. This means that as the power consumption increases or decreases, the motor speed will correspondingly increase or decrease. The number of ampere-hours, watt-hours, and kilowatt-hours being used at the time do not directly affect the motor speed of the utility meter.