JEE MainPhysicsCurrent Electricity
A student measures the V-I characteristics of a resistor of true resistance R using a non-ideal voltmeter and a non-ideal ammeter. The student plots the voltmeter reading V on the y -axis and the ammeter reading I on the x -axis. The experiment is performed using two different circuit configurations: Setup I: The voltmeter is connected in parallel across the resistor R , and the ammeter is connected in series with th
Options
- Am₂ < R < m₁
- BR < m₁ < m₂
- Cm₁ = m₂ = R
- Dm₁ < R < m₂
Correct answer
D. m₁ < R < m₂
Step-by-step solution
Let the resistance of the non-ideal voltmeter be R_V and that of the non-ideal ammeter be R_A . In Setup I, the voltmeter is in parallel with R . The ammeter measures the total current I which is the sum of the current through R and the current through the voltmeter. Thus, I = V R + V R_V . The slope of the V-I graph is m₁ = V I = R R_V R + R_V . Because this is the equivalent resistance of R and R_V in parallel, m₁ In Setup II, the ammeter is in series with R . The voltmeter measures the total voltage V across the