An ammeter A of finite resistance and a resis | vedclass

Name: Exam Paper Generator | JEE NEET Paper Generator | Vedclass
Brand: Vedclass
Rating: 5 (35 reviews)

Question

(A) potentiometer is considered an ideal device that draws negligible current from the circuit,meaning its effective resistance is infinite. Thus,the

Vedclass · Accepted Answer

$I > I_0, V < V_0$

Vedclass · Answer

(A) potentiometer is considered an ideal device that draws negligible current from the circuit,meaning its effective resistance is infinite. Thus,the initial circuit behaves as if $R$ is connected directly to the cell $C$ through the ammeter $A$.When the potentiometer is replaced by a voltmeter of finite resistance $R_v$,the voltmeter acts as a resistor in parallel with $R$. The equivalent resistance of the parallel combination $(R || R_v)$ is less than $R$. Since the total resistance of the circuit decreases,the total current drawn from the ideal cell $C$ increases. Therefore,the ammeter reading $I$ is greater than the initial reading $I_0$ $(I > I_0)$.Because the ammeter has a finite resistance $R_A$,the voltage drop across the ammeter increases as the current increases. Since the cell $C$ is ideal (constant $EMF$ $E$),the voltage across the parallel combination $(R || R_v)$ is $V = E - I R_A$. Since $I > I_0$,it follows that $V < V_0$.

Similar Questions

The heat evolved or absorbed at the junction when an electric current passes through the junction of two different metals is known as which effect?

The net current flowing in the given circuit is . . . . . . $\text{A}$.

An ammeter and a voltmeter are connected in series with a cell. Their readings are $A$ and $V$ respectively. If a resistor is now connected in parallel with the voltmeter,then:

The voltage drop across the $15\, \Omega$ resistance in the given figure is $.....V.$

Vedclass Test Series

Exam Paper Generator

Online Exam Module