Question 1

Moving Iron instruments can be used on:

Accepted Answer

Moving Iron instruments are designed to measure electrical quantities and can operate on both alternating current (AC) and direct current (DC) systems. This versatility is due to the principle of operation, which relies on the magnetic effect of electric current, making them suitable for both types of electrical systems.

Question 2

In spring control instruments, controlling torque:

Accepted Answer

In spring control instruments, the controlling torque is determined by the spring's properties and is not easily adjustable.

Question 3

Chemical effect is used for the operation of:

Accepted Answer

The ampere-hour meter operates based on the chemical effect of electric current. It measures the quantity of charge flow through a circuit over time, often used in applications like battery charge-discharge cycles, where the chemical effect is directly related to the operation.

Question 4

The deflection torque can be produced by:

Accepted Answer

Deflection torque can be produced magnetically, as it involves the interaction of magnetic fields to create a torque that causes deflection.

Question 5

Moving coil instruments are:

Accepted Answer

Moving coil instruments are both permanent magnet type and dynamometer type.

Question 6

For increasing the range of an ammeter, connect:

Accepted Answer

A low value resistance, known as a shunt, is connected in parallel with the ammeter coil to increase its range. This allows a portion of the current to bypass the meter, enabling it to measure higher currents without being damaged.

Question 7

A galvanometer can be used for measuring current and voltage of a circuit by:

Accepted Answer

A galvanometer can be converted into an ammeter to measure current by connecting a low resistance (shunt) in parallel with it, and into a voltmeter to measure voltage by connecting a high resistance in series with it.

Question 8

The energy consumption of MI instrument as compared to MC instrument is:

Accepted Answer

MI (Moving Iron) instruments generally consume more energy compared to MC (Moving Coil) instruments because the former relies on magnetic effects that require more power to generate the necessary magnetic field for operation. MC instruments, on the other hand, are more efficient and designed for lower power consumption.

Question 9

An ammeter requires a change of 4A in its coil to produce a pointer deflection of 8mm then its sensitivity is

Accepted Answer

Sensitivity is defined as the deflection per unit of measurement, in this case, mm per ampere (mm/A). Given a deflection of 8mm for a 4A change, sensitivity = 8mm / 4A = 2.0 mm/A.

Question 10

Electrostatic type instruments are mainly used for measurement of

Accepted Answer

Electrostatic type instruments are primarily used for measuring high voltages because they rely on the principle of electrostatic force, which is suitable for accurately measuring high voltage levels without significant power consumption.

Question 11

Measurement range of a voltmeter can be extended by using:

Accepted Answer

The measurement range of a voltmeter can be extended by using high series resistance. This allows the voltmeter to measure higher voltages by dividing the voltage across the series resistor and the voltmeter, effectively reducing the voltage the voltmeter directly measures.

Question 12

Which of the following voltmeter have least power consumption:

Accepted Answer

Electrostatic voltmeters have the least power consumption among the options given because they measure voltage without drawing current from the circuit.

Question 13

Which of the following instruments have least torque/weight ratio:

Accepted Answer

The answer of Which of the following instruments have least...

Question 14

Fluid friction damping can be used in

Accepted Answer

The answer of Fluid friction damping can be used in
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Question 15

The ratio and phase angle errors in potential transformer may be reduced by

Accepted Answer

The ratio and phase angle errors in a potential transformer are not reduced by increasing the exciting current, increasing the resistance and leakage reactance, or by not employing turns compensation. These actions would typically worsen the performance or have no beneficial effect on reducing errors.

Question 16

A voltmeter should have

Accepted Answer

A voltmeter is designed to measure the voltage difference between two points in an electrical circuit without drawing any significant current. To achieve this, it must have high internal resistance to minimize the current it draws from the circuit, ensuring that its presence does not alter the voltage it is intended to measure.

Question 17

The major advantage of electromagnet type meter over a permanent magnet meter is

Accepted Answer

The answer of The major advantage of electromagnet type meter...

Question 18

The change in the direction of a compass needle, when a current carrying wire is brought near, is called

Accepted Answer

This phenomenon is known as electromagnetic deflection because it involves the interaction between the magnetic field created by the electric current in the wire and the magnetic field of the Earth, which affects the compass needle's direction.

Question 19

The use of _____ instruments is merely confined within laboratories as standardizing instruments.

Accepted Answer

Absolute instruments are primarily used in laboratories for the purpose of standardization, as they measure electrical quantities directly from the fundamental units without requiring any prior calibration against a standard.

Question 20

Which of the following instruments indicate the instantaneous value of the electrical quantity being measured at the time at which it is being measured ?

Accepted Answer

Indicating instruments are designed to show the instantaneous value of an electrical quantity at the moment of measurement. They directly display readings on a dial or a scale, allowing users to observe the current value of voltage, current, etc., at any given instant.

Quiz 1: Electrical Instrumentation