WorksheetsQuiz 4
Total questions: 10
Worksheet time: 12mins
Spring-controlled moving-iron instruments exhibit a square law response resulting in a non-linear scale. The shape of the scale can be made almost linear by
keeping rate of change of inductance L, with deflection θ as constant
keeping as 1/ θ and dL/dθ constant
keeping as θ and dL/dθ constant
keeping as 1/ kθ constant, where k is the spring constant
A moving-coil instrument has the following data: number of turns = 100, width of coil = 20 mm, depth of coil = 30 mm, flux density in the gap = 0.1 Wb/m2. Calculate the deflecting torque when carrying a current of 10 mA.
60x10-6 N m
30x10-6 Nm
120x10-6 Nm
90x10-6 Nm
In a series-type ohmmeter
zero marking is on the left-hand side
zero marking is at the centre
zero marking is on the right-hand side
zero marking may be either on left or right-hand side
In series type ohmmeters, zero adjustment should be done by
changing the shunt resistance across the meter movement
changing the series resistance
changing the series and the shunt resistance
changing the battery voltage
Shunt-type ohmmeters have a switch along with the battery to
disconnect the battery when not in use
prevent meter from getting damaged when measuring very low resistances
compensate for thermo-emf effects by reversing battery polarity
which is true regarding MI instruments
more sensitive
deflection is proportional to θ
measuring both ac & dc
all the above
‘∞’ at the extreme right and ‘0’ at the extreme left scale for
Shunt type ohm meter
Series type ohm meter
all the above
none of the above
Multipliers are connected in --------- with the basic meter for extending Voltmeter
Parallel
Series
none of the above
A 1mA meter movement with an internal resistance of 100 Ω is to be converted into (0-10) mA. What is the value of multiplying factor
(a)
A basic meter with an internal resistance of 100 Ω and f.s.d current of 2 mA,is to be converted in to a multi range dc voltmeter with ranges of (0-10)V,find the value of Rs
4.9 kΩ
14.9 kΩ
24.9 kΩ
34.9 kΩ
