Quiz: Electrical Engineering
Exam: UPPSC AE
Topic: Measurement and measuring instrument
Each question carries 1 mark.
Negative marking: 1/4 mark
Time: 10 Minute
1.Range of an electrical instrument depends on __________
2. Potential terminals have a __________
a) high current capacity
b) low voltage capacity
c) low current capacity
d) high voltage capacity
3.What is the condition for using a multiplier in A.C. voltmeters?
a) by using ac supply
b) by maintaining a uniform impedance
c) by maintaining a uniform frequency
d) by using a galvanometer
4. What is the relation between the balance equation and the magnitude of input voltage?
a) directly proportional
c) inversely proportional
d) depends on the null indicator
5. Accuracy of bridge circuit depends on _________
a) component values
b) null detector
c) voltage source
d) current source
6.The bridge circuit can be used in _________
a) high voltage circuits
b) low power circuits
c) control circuits
d) digital integrated circuits
7. What are the physical parameters that are to be controlled when a bridge is used in control applications?
a) area and volume
b) mass and weight
c) pressure and temperature
d) current and voltage
8.Induction type instruments are used for ____________
a) A.C. measurements
b) D.C. measurements
c) Resistance measurements
d) Voltage measurements
9.What is the effect of eddy currents in the aluminum disc?
a) varies by a factor of twice the disc length
b) independent of the disc speed
c) varies by a factor of four times the disc size
d) proportional to the disc speed
10.Resistance of pressure coil in a low power factor dynamometer type wattmeter is
a) once time
b) three times
c) hundred times
d) ten times
Sol.1 Ans (a)
The amount of current safely passing through the coil of the instrument and the spiral springs. This acts as the leads of the current to the instrument. As a result, the range of an electrical instrument depends on the current.
Sol.2 Ans (c)
A shunt is normally a very low value of resistance, connected in parallel with the ammeter coil. In a shunt, the potential terminals have a low current carrying capacity. As a result, a low range ammeter is used to measure the large current.
Sol.3 Ans (c)
A multiplier can be used for A.C. voltmeters. The condition to be satisfied is that the total impedance of the voltmeter and the multiplier circuit must be constant for a wide range of frequencies.
Sol.4 Ans (c)
The input voltage does not appear in the expression for the balance equation. Thus, balance equation is independent of the magnitude of input voltage.
Sol.5 Ans (a)
The accuracy of measurement of a bridge circuit depends on the values of the components used in it. Voltage source supplies dc bias to the circuit while the detector is used for balance condition.
Sol.6 Ans (c)
The bridge circuit is generally used in control applications. Control systems make use of bridge circuits for industrial applications.
Sol.7 Ans (c)
In control applications, when one of the arms of the bridge circuit consists of a resistance element, sensitive physical parameters such as pressure and temperature are to be controlled.
Sol.8 Ans (a)
A.C. measurements are made using Induction type instruments. Induction type energy meter is used to measure the energy that is consumed in A.C. circuits only.
Sol.9 Ans (d)
The eddy currents induced in an aluminum disc vary in proportion to the speed of the disc. As a result, the braking torque exerted on the disc varies in proportion to the speed.
Sol.10 Ans (d)
In a low power factor dynamometer type wattmeter, pressure coil has a resistance value that is one tenth of the actual with respect to unity power wattmeter. This is done in order to ensure a reasonable amount of torque at low power factors.