Measurement Methods and Instruments

What are the two main methods of measurement?

• Experimental and Observational

• Descriptive and Analytical

• Statistical and Theoretical

• Qualitative and Quantitative

Define absolute and secondary instruments.

• Absolute instruments are only used in laboratories.

• Absolute instruments provide direct measurements, while secondary instruments rely on primary standards for accurate measurements.

• Secondary instruments can measure without calibration.

• Absolute instruments require external power sources.

What is the difference between analog and digital instruments?

• Analog instruments use continuous signals; digital instruments use discrete values.

• Analog instruments are only used in older technology.

• Analog instruments are more accurate than digital instruments.

• Digital instruments use continuous signals; analog instruments use discrete values.

Explain the null and deflection type instruments.

• Null type instruments measure voltage directly; deflection type instruments require no reference.

• Null type instruments use a digital display; deflection type instruments are purely mechanical.

• Null type instruments are used for high-frequency measurements; deflection type instruments are for low-frequency measurements.

• Null type instruments balance against a reference; deflection type instruments measure by observing deflection from a zero position.

What are indicating, integrating, and recording instruments?

• Indicating instruments measure temperature, integrating instruments display pressure, and recording instruments analyze sound.

• Indicating instruments calculate averages, integrating instruments show trends, and recording instruments summarize events.

• Indicating instruments show measurements, integrating instruments compute totals, and recording instruments log data.

• Indicating instruments provide alerts, integrating instruments visualize data, and recording instruments transmit signals.

What is deflecting torque in measurement instruments?

• Deflecting torque is the torque that causes movement in measurement instruments to indicate a value.

• Deflecting torque is the resistance that prevents movement in measurement instruments.

• Deflecting torque is the energy required to power measurement instruments.

• Deflecting torque is the force that stabilizes measurement instruments.

Describe controlling torque and its function.

• Controlling torque only affects the electrical components of a machine.

• Controlling torque is the torque used to regulate the speed and position of rotating objects, ensuring stability and precision in mechanical systems.

• Controlling torque is the force applied to stop an object from rotating.

• Controlling torque is irrelevant in mechanical systems and has no function.

What is damping torque and how is it produced?

• Damping torque is a resistive torque that opposes motion, produced by friction, air resistance, or electromagnetic forces.

• Damping torque is a type of energy that accelerates motion, produced by gravity.

• Damping torque is a magnetic force that increases speed, produced by electric currents.

• Damping torque is a force that enhances motion, produced by springs.

Explain the working principle of PMMC instruments.

• PMMC instruments work by using a current-carrying coil in a magnetic field to produce a torque that causes rotation, which is measured on a scale.

• PMMC instruments measure voltage using a thermocouple.

• PMMC instruments operate by using a piezoelectric crystal to generate readings.

• PMMC instruments rely on a digital display to show measurements.

What is the construction of MI type instruments?

• A moving iron element, a capacitor, and a lever

• MI type instruments are constructed with a moving iron element, a coil, a spring, and a scale.

• A moving coil element, a magnet, and a dial

• A fixed iron element, a battery, and a digital display