In an electric circuit, a rheostat is commonly used to change which of the following quantities?
AResistance
BTemperature
CElectric charge
DMagnetic flux
Answer & Solution
Correct answer: A. Resistance
1. A rheostat is a variable resistor with a sliding contact.
2. Moving the slider changes the length of wire in the circuit, changing the resistance.
3. By varying resistance, it controls the current; the quantity it directly changes is resistance.
_Source: RRB Group D CEN-02/2018 PYQ, Q.2._
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