Correct Answer - Option 2 : 100 Ω / volt
Concept:
The maximum loading effect is caused by an instrument having the lowest sensitivity.
Sensitivity:
- It is also called a Figure of merit or Scale Factor.
- It indicates the relation between change in output readings for change in input reading for an instrument.
- This relation may be linear or nonlinear.
Sensitivity S = Change in output / Change in Input
In the given meters,
100 Ω/volt has the least sensitivity
Important Point:
Loading effect:
When an instrument of lower sensitivity is used with a heavier load the measurement it makes is incorrect, this effect is known as the loading effect.
The given meter is voltmeter as the sensitivity is mentioned in Ω/volt
Loading effect in Voltmeter:
- When a voltmeter is connected across a resistor to measure voltage, the voltmeter draws current for its working.
- Then as voltmeter internal resistance is in parallel with the resistance (whose voltage is to be measured) resultant resistance decreases.
- Then voltmeter ready less than the actual value. It is called the loading effect.
To reduce the loading effect, high sensitivity voltmeters to be selected for the same range.
