Electrical Measurements and Instrumentation MCQs (Part-6)
What is the main function of a wattmeter?
A Measure frequency
B Measure power
C Measure voltage
D Measure resistance
A wattmeter is used to measure the electrical power in a circuit. It works by measuring both the voltage and the current, then calculating the power (in watts) being consumed by the load. Wattmeters are crucial in power analysis and electrical system management.
What type of instrument is an energy meter?
A Frequency measurement
B Power measurement
C Voltage measurement
D Energy consumption
An energy meter is designed to measure the total electrical energy consumed by a system or device over time. It is commonly used for billing purposes in residential and industrial applications and is calibrated in kilowatt-hours (kWh).
Which device is used to measure resistance in a circuit?
A Ohmmeter
B Wattmeter
C Ammeter
D Voltmeter
An ohmmeter is a device used to measure the electrical resistance of a component or circuit. By applying a known voltage and measuring the resulting current, it calculates resistance using Ohm’s Law. This instrument is vital for testing circuits and components.
Which device measures the frequency of an AC signal?
A Oscilloscope
B Voltmeter
C Frequency meter
D Ammeter
A frequency meter is used to measure the frequency of an alternating current (AC) signal, typically in hertz (Hz). It counts the number of cycles per second of an AC signal, which is essential in power systems, signal processing, and communication systems.
What is the function of a galvanometer?
A Measure power
B Measure small currents
C Measure large currents
D Measure resistance
A galvanometer is a highly sensitive instrument used to measure very small electrical currents. It works on the principle of electromagnetic deflection, where the current passing through a coil generates a magnetic field, causing a needle to move.
Which of the following instruments can measure both DC and AC voltages?
A Multimeter
B Wattmeter
C Frequency meter
D Ohmmeter
A multimeter is a versatile instrument that can measure various electrical parameters, including DC and AC voltages, current, and resistance. It is a must have tool for electricians, technicians, and engineers for diagnosing and troubleshooting electrical circuits.
Which sensor is used to measure temperature?
A Pressure sensor
B Flow meter
C Strain gauge
D Thermocouple
A thermocouple is a type of temperature sensor that measures temperature by converting thermal energy into a small electrical voltage. It is widely used due to its simple design, wide temperature range, and fast response time.
What is the primary purpose of a transducer in electrical measurement systems?
A Measure power
B Measure voltage
C Convert energy forms
D Measure resistance
A transducer is a device that converts one form of energy, such as mechanical, thermal, or light energy, into an electrical signal. This conversion is crucial for measuring physical phenomena, such as temperature, pressure, and force, in electrical systems.
What does a potentiometer measure?
A Voltage
B Resistance
C Current
D Power
A potentiometer is an instrument used to measure the unknown voltage by balancing it against a known reference voltage. It is highly accurate and often used in laboratories and precision measurement tasks to ensure accurate voltage readings.
Which of the following instruments is used to measure the phase angle between two AC signals?
A Wattmeter
B Frequency meter
C Multimeter
D Phase meter
A phase meter measures the phase difference between two AC signals. This is crucial in analyzing the synchronization between voltage and current in AC circuits. Phase measurements help ensure that AC systems operate efficiently.
Which device is used to step down high voltage in a system?
A Ammeter
B Potential transformer
C Multimeter
D Current transformer
A potential transformer (PT) is used to step down high voltage levels in power systems to a safer, measurable level. This is essential for voltage measurement, protection relays, and other instruments that operate at lower voltages.
What type of measurement does an oscilloscope perform?
A Voltage
B Power
C Signal waveform
D Frequency
An oscilloscope is used to observe and display electrical signals in the form of waveforms. It provides real time visual representation of voltage changes over time, making it invaluable for analyzing the behavior of electrical circuits and troubleshooting.
What does a strain gauge measure?
A Strain
B Resistance
C Pressure
D Current
A strain gauge measures the deformation (strain) in a material when subjected to a force. As the material deforms, the resistance of the strain gauge changes, and this change is used to calculate the strain.
Which device is used for measuring electrical power in an industrial system?
A Ammeter
B Energy meter
C Voltmeter
D Wattmeter
A wattmeter is designed to measure the electrical power (in watts) consumed by a load in industrial systems. It works by measuring the voltage and current and calculating the real power, which is important for load management and energy efficiency in industries.
What is the main function of a current transformer (CT)?
A Step down current
B Measure resistance
C Step down voltage
D Measure power
A current transformer (CT) is used to step down high currents in a power system to a safer, measurable level. This allows instruments to measure large currents safely without direct exposure to high current levels, ensuring accurate monitoring of electrical systems.