Two cells of same emf E but internal resistance r1 and r2 are connecte – InterviewSolution

InterviewSolution

1.

Two cells of same emf E but internal resistance r1 and r2 are connected in series to an external resistor R (Fig.). What should be the value of R so that the potential difference across the terminals of the first cell becomes zero.

Answer»

\(I=\frac{E+E}{R+r_1+r_2}\)

V₁ = E - Ir₁ = E - \(\frac{2E}{r_1+r_2+R}r_1=0\)

or \(E=\frac{2Er_1}{r_1+r_2+R}\)

\(\Rightarrow\) r₁ + r₂ + R = 2r₁

\(\Rightarrow\) R = r₁ - r₂

Discussion

No Comment Found

Related InterviewSolutions

Name a substance of which the resistance remains almost unchanged by the increase in temperature.
The graph shown here shows the variation of terminal potential difference V, across a combination of three cells in series to a resistor, versus current i:(i) Calculate the emf of each cell.(ii) For what current i, will the power dissipation of the circuit be maximum?
The plot of the variation of potential difference across a combination of three identical cells in series, versus current is shown below. What is the emf and internal resistance of each cell?
The plot of the variation of potential difference across a combination of three identical cells in series, versus current is shown alongside. What is the emf and internal resistance of each cell?
Nichrome and copper wires of same length and same radius are connected in series. Current I is passed through them. Which wire gets heated up more? Justify your answer.
What will be the equilibrium resistance between points A & D(A) 10 Ω(B) 20 Ω(C) 30 Ω(D) 40Ω
Two heater wires of equal lengths are first connected in series and then in parallel. The ratio of heat produced in two cases is(A) 2:1(B) 1:2(C) 4:1(D) 1:4
What is the net resistance between A and B?(A) R(B) 5R(C) 3R(D) 6R
The rate of flow of charge through any wire is called …………
The net flow of charge at any point in the conductor is ………