Practice Quiz for Mid-I

In spring controlled moving iron instruments, the scale is----

• Uniform

• Cramped at the lower end and expanded at the upper end

• Expanded at the lower end and cramped at the upper end

• Cramped both at the lower and the upper ends

The range of an electrostatic voltmeter can be extended by using-----------------------------------------------------

• (a) A capacitor in series with the voltmeter whose capacitance is greater than the capacitance of the voltmeter

• (b) A capacitor in series with the voltmeter whose capacitance is smaller than that in an electrostatic field

• (c) A resistor in series with the voltmeter

• (d) an inductor in series with the voltmeter

A moving iron instrument can be used for current and voltage measurements---------------------------------

• (a) In ac circuits only

• in dc circuits only

• in both a.c. and d.c. circuits for any value of frequency (in case of a.c. circuits)

• in both a.c. and d.c. circuits for frequencies upto 125Hz (in case of a.c. circuits)

Electrostatic type instruments are primarily used as---------

• (a). Ammeters

• (b) wattmeters

• (c) voltmeters

• (d) ohmmeters

An electrostatic voltmeter draws a small value of current on dc----------------------------------------------------

• (a). Under steady state condition respective of the applied voltage

• (b). when switched on irrespective of the applied voltage

• (c). when measuring low voltage

• (d). when measuring high voltages

The disadvantages of shunts for use at high currents are-----

• (a). It is difficult to achieve good accuracy with shunts

• (b). power consumption of the shunts is large

• (c). the metering circuit is not electrically isolated from the power circuit

• (d) all the above

The disadvantages of using multipliers with voltmeter at high voltages are--------------------------------------

• (a) The power consumption of multipliers becomes large at large voltages

• (b). The multipliers at high voltages have ti be shielded in order to prevent capacitive currents

• (c). The metering circuit is not electrically from the power circuit

• (d). all of the above

The power in a d.c. circuit is measured with the help of ammeter and a voltmeter. The voltmeter is connected on the load side. The power indicated by the product of readings of two instruments is-----------------------------------

• (a).The power consumed in the load

• (b). the sum of power consumed by load and the voltmeter

• (c). the sum of power consumed by load and the ammeter

• (d). none of the above

In an electrodynamometer type of wattmeter---------------------

• (a). The current coil is made

• (b). the pressure coil is fixed

• (c). any of two coils i.e. current coil or pressure coil can be made fixed

• (d). both the coils should be movable

When measuring power with an electrodynamometer wattmeter in a circuit where the load current is large---

• (a) The current coil should be connected on the load side

• (b). the pressure coli should be connected on the load side

• (c). The coil should be connected on the supply side

• (d). it is immaterial whether the pressure coil or the current is on the load side