Measurements & Instrumentation Quiz – Set 1

The household energy meter is

Consider the following statements: In a differential amplifier using JFET, the differential output offset is due to

1. mismatch between FET parameters
2. difference in values of resistances used in circuit
3. variation in supply voltage.

Of the statements, the correct statements are

It is required to measure angular position. Out of the transducers

1. Circular potentiometer
2. LVDT
3. E pick up
4. Synchro

The proper devices are

In two wattmeter method of 3 phase power measurement, when does one wattmeter read negative

A dynamometer wattmeter is connected in ac circuit. The reading will be

Potentiometer method of dc voltage measurement is more accurate than direct measurement using a voltmeter because

In a strain measuring device using a strain gauge, the output quantity is

The coil of a moving iron instrument has a resistance of 500 Ω and an inductance of 1 H. It reads 250 V when a 250 V dc is applied. If series resistance is 2000 Ω, its reading when fed by 250 V, 50 Hz ac will be

Two resistors R₁ = 36 Ω ± 5% and R₂ = 75 Ω ± 5% are connected in series. The total resistance is

Which of the following voltmeters would you use for measuring voltage across 20 kΩ resistance?

A single phase energy meter has the rating 1200 resolutions/ kWh. If a 500 W electric gadget is used for 4 hours, the energy meter will make

Which of the following statement is correct for two wattmeters method of power measurement in 3 phase circuit?

Magnetic flux density has the dimensions

An LVDT is used to measure displacement. The LVDT feeds a Voltmeter of 0-5 V range through a 250 gain amplifier. For a displacement 0.5 mm the output of LVDT is 2 mV. The sensitivity of instrument is

A voltmeter using thermocouples measures

Which of the following are needed both for protection and metering?

Which of the following measurements using a dc potentiometer do not require standardisation of potentiometer?

To increase Q factor of a coil, the wire should be

A standard cell of 1.0185 V is used with a slide wire potentiometer. The balance was obtained at 60 cm. When an unknown emf was connected, the balance was obtained at 82 cm. The magnitude of unknown emf is

A moving coil instrument has a resistance of 0.6 Ω and full scale deflection at 0.1 A. To convert it into an ammeter of 0-15 A range, the resistance of shunt should be

In a thermocouple temperature transducer, the output voltage is usually measured by

If reference sound pressure P₀ is 2 x 10^-5 N/m², a sound pressure of 90 dB is equal to

An ammeter of 0-25 A range has a guaranteed accuracy of 1% of full scale reading. The current measured is 5 A. The limiting error is

Assertion (A): A hot wire ammeter has a cramped scale.
Reason (R): The heat is proportional to square of current.

A meter with a resistance of 100 Ω and a full scale deflection of current of 1 mA is to be converted into voltmeter of 0 - 5 V range. The multiplier resistance should be

In a resistance strain gauge, G = 2, stress = 1050 kg/cm², R = 1000 Ω. The value of ΔR will be

In figure the bridge is balanced when Z4 is

The Lissajous pattern observed on screen of CRO is a straight line inclined at 45° to x axis. If X-plate input is 2 sin ωt, the Y-plate input is

In a ballistic galvanometer, a charge of 100 μC gives a first swing of 25°. The charge required to cause first swing of 50° is

Assertion (A): When a wattmeter is used for low impedance loads, the pressure coil is connected across the load.
Reason (R): A wattmeter measures apparent power.

In a CRO which of the following is not a part of electron gun

In 3 phase power measurement by two wattmeter method, the reading of one wattmeter is zero. The power factor of load is

Assertion (A): De sauty's bridge is suitable only for pure capacitor.
Reason (R): Capacitors are mostly perfect.

Figure shows an RC potentiometer to measure ac voltage. It is desired that V₀/V_i should be independent of frequency. The value of C should be

A moving coil instrument has a resistance of 0.5 Ω and a full scale deflection of 0.1 A. To convert it into an ammeter of 0-10 A the shunt resistance should be

Which of the following is true about an impulse voltage?

As per BIS there are 6 accuracy classes of instruments.

The coil of a moving coil meter has 100 turns, is 40 mm long and 30 mm wide. The control torque is 240 x 10^-6 N-m on full scale. If B = 1 Wb/m², range of meter is

The speed transducer using a drag cup rotor has the main advantage of

A digital voltmeter has a read out range from 0 to 999 counts. If the full scale reading is 9.999 V, the resolution is

Induction wattmeter can be used in

Loss of charge method is suitable for medium resistances.

The angle δ for a mica capacitor is about

A dynamometer wattmeter is connected in ac circuit. The measured power is

A digital frequency counter can be converted to DVM by addition of a suitable

A moving iron instrument gives correct reading when used at

A piezoelectric force transducer has a charge sensitivity of 20 pC/N. It is connected to a charge amplifier and overall gain of transducer and amplifier is 50 mV/N. The gain of amplifier is

In which of the transformer is the secondary nearly short circuited under normal operating conditions?

In figure, Z₁ = 200∠60° Ω, Z₂ = 400∠ - 90° Ω, Z₃ = 300∠0°. Then Z₄ for bridge to be balanced is