Electrical Measurements and Instrumentation MCQs (Part-5)
Which device is used to measure the power consumed in an electrical circuit?
A Ohmmeter
B Voltmeter
C Wattmeter
D Ammeter
A wattmeter measures the real power consumed by an electrical load in a circuit. It works by measuring both the voltage across the load and the current flowing through it, and then calculating the power in watts. Wattmeters are essential in power distribution systems to monitor energy usage.
What does an energy meter measure?
A Energy consumption
B Power
C Voltage
D Current
An energy meter is used to measure the electrical energy consumed by a system or device over time. It is calibrated in kilowatt-hours (kWh), and it plays a key role in billing for electrical usage in residential, commercial, and industrial settings.
Which instrument is used to measure both current and voltage in a circuit?
A Wattmeter
B Multimeter
C Ammeter
D Voltmeter
A multimeter is a versatile measuring device that can measure various electrical quantities such as current, voltage, and resistance. It combines the functions of an ammeter, voltmeter, and ohmmeter into one tool, making it essential for troubleshooting and testing electrical circuits.
Which of the following is used to measure very high voltages?
A Oscilloscope
B Galvanometer
C Ammeter
D High voltage probe
A high voltage probe is used for safely measuring high voltage levels in electrical systems. It is designed to handle the high electrical stress without damaging the measuring equipment and provides a scaled down measurement for accurate readings.
What is the main function of a transducer in electrical measurement?
A Convert energy form
B Measure current
C Measure power
D Generate voltage
A transducer converts one form of energy (e.g., mechanical, thermal, or light energy) into an electrical signal. This conversion allows for easier measurement and analysis of physical parameters in a variety of applications, including temperature and pressure measurements.
What is the purpose of a frequency meter in electrical measurements?
A Measure power
B Measure voltage
C Measure frequency
D Measure current
A frequency meter is used to measure the frequency of an alternating current (AC) signal. It helps determine the number of cycles per second (hertz) of an electrical waveform, which is crucial for analyzing and ensuring the proper functioning of electrical systems and equipment.
Which device is used to measure small currents with high sensitivity?
A Voltmeter
B Galvanometer
C Wattmeter
D Ammeter
A galvanometer is an instrument used to measure small currents with high precision. It works on the principle of electromagnetic deflection and is often used in laboratory experiments and other sensitive measurement applications. It is part of more complex instruments like multimeters.
What type of sensor is used to measure strain?
A Pressure sensor
B Thermocouple
C Displacement sensor
D Strain gauge
A strain gauge is used to measure strain (deformation) in a material when it is subjected to an external force. It works by detecting changes in the electrical resistance of the material as it deforms. Strain gauges are widely used in structural and mechanical testing.
What does a strain gauge measure in a material?
A Strain
B Pressure
C Temperature
D Displacement
A strain gauge measures the deformation or strain in a material when subjected to an external force. It detects changes in electrical resistance as the material stretches or compresses, and these changes are used to calculate the strain.
What principle does a piezoelectric sensor operate on?
A Change in capacitance
B Generation of electrical charge under stress
C Change in resistance
D Change in voltage
Piezoelectric sensors generate an electrical charge when subjected to mechanical stress. This makes them ideal for measuring pressure, vibration, and acceleration, as the generated charge is proportional to the applied force or pressure.
How does thermal noise affect electrical measurements?
A Increases precision
B Increases accuracy
C Reduces power consumption
D Reduces signal clarity
Thermal noise, also known as Johnson Nyquist noise, is caused by the random motion of electrons in a conductor. This noise can distort electrical signals and reduce the clarity and accuracy of measurements, especially in low signal applications.
What is the function of shielding in electrical measurements?
A Increase signal speed
B Increase signal strength
C Prevent signal noise
D Reduce signal distortion
Shielding is used in electrical systems to prevent electromagnetic interference (EMI) and noise from affecting the accuracy of measurements. It involves enclosing sensitive components in a conductive material that blocks unwanted external signals.
What does a displacement sensor typically measure?
A Position or movement
B Speed
C Temperature
D Pressure
A displacement sensor measures the position or movement of an object relative to a reference point. It is often used in applications like automation, robotics, and structural testing to monitor precise changes in position.
What does a torque sensor measure?
A Voltage
B Pressure
C Rotational force
D Speed
A torque sensor measures the rotational force or torque applied to a rotating object. It works by detecting the deformation or twisting force experienced by a rotating shaft and converting it into a measurable electrical signal.
What type of noise is commonly reduced using filters in electrical measurement systems?
A Electromagnetic interference (EMI)
B White noise
C Random noise
D Thermal noise
Electromagnetic interference (EMI) is a common source of noise that affects measurement systems. Filters are used to reduce EMI by blocking unwanted high frequency signals while allowing the desired signal to pass through, improving the accuracy and clarity of measurements.