Student Login

Home›Chapters›Current Electricity PYQs›Cells: EMF, Internal Resistance & Combinations›Question 47

NEET 2006 (AIPMT) · Cells: EMF, Internal Resistance & Combinations

Cells: EMF, Internal Resistance & Combinations question from NEET 2006 (AIPMT)

Q47NEET 2006 · AIPMTMedium

Cells: EMF, Internal Resistance & Combinations

Two cells, having the same e.m.f. are connected in series through an external resistance R. Cells have internal resistances r1 and r2 (r1 > r2) respectively. When the circuit is closed, the potential difference across the first cell is zero. The value of R is

Show answer and solution

Answer: (b)

$I = \frac{2E}{R + r_1 + r_2}$
P.d. across first cell zero: $E = Ir_1 \Rightarrow \frac{2E r_1}{R + r_1 + r_2} = E$
$R + r_1 + r_2 = 2r_1 \Rightarrow R = r_1 - r_2$ . So the answer is (b).

Report a mistake

More questions on Cells: EMF, Internal Resistance & Combinations

An energy source will supply a constant current into the load if its internal resistance…JEE Main 2005 (AIEEE)
Two batteries, one of emf 18 volts and internal resistance 2 Ω and the other of emf 12…NEET 2005 (AIPMT)
Two sources of equal emf are connected to an external resistance R. The internal…JEE Main 2005 (AIEEE)
For a cell terminal potential difference is 2.2V when circuit is open and reduce to 1.8 V…NEET 2002 (AIPMT)
A cell has an emf 1.5 V. When connected across an external resistance of 2 Ω, the…NEET 2000 (AIPMT)
The internal resistance of a cell of emf 2 V is 0.1 Ω. It is connected to a resistance of…NEET 1999 (AIPMT)
A battery of e.m.f 10 V and internal resistance 0.5 Ω is connected across a variable…NEET 1992 (AIPMT)
Two identical batteries each of e.m.f 2 V and internal resistance 1 Ω are available to…NEET 1990 (AIPMT)