Electronics and Communication Engineering - Measurements and Instrumentation

31.
Two resistances R1 = 18.7 Ω. and R2 = 3.624 Ω in series. The total resistance to the appropriate number of significant figures is
22.324 Ω
22.32 Ω
22.3 Ω
22 Ω
Answer: Option
Explanation:

Since second and third decimal places of R1 are not known, we can take only first decimal place of R2.


32.
The input impedance of CRO is about
zero
10 Ω
100 Ω
one mega ohm
Answer: Option
Explanation:

CRO has very high input impedance.


33.
Which of the following is not correct in respect of electrostatic instrument?
It is essentially a voltmeter
It is suitable for only high voltages
It has a uniform scale
It can be used for both ac and dc
Answer: Option
Explanation:

The scale of electrostatic voltmeter is not uniform.


34.
The wave applied to X plates, for ohtaining trace of voltage wave, is
sawtooth wave
sinusoidal wave
rectangular wave
either (a) or (c)
Answer: Option
Explanation:

It is called time base signal.


35.
The response of a thermistor overs the whole of its temperatures range is
linear
non-linear
almost linear
either (a) or (c)
Answer: Option
Explanation:

It is a non-linear device. The change of resistance with temperature is non-linear.