Sign in
12thPass logo
New chatPYQ LibraryDoubtsRank report
Sign in to see Recents

Your guest activity stays on this device

Sign in to save progress →
Sign in

Current Electricity question

2006 · Q132
Guest · filters and generic practice availableBrowsing as a guest · PYQ filters and generic practice are available. Sign in only for personalised features and saved progress.
  1. PYQ Library
  2. /NEET
  3. /Physics
  4. /Current Electricity
  5. /2006 · Q132

Current Electricity question

2006 · Q132

NEETPhysicsCurrent ElectricityMCQ+4 / −1
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
  1. A
    r1 + r2
  2. B
    r1 −-− r2
  3. C
    r1+r22{{{r_1} + {r_2}} \over 2}2r1​+r2​​
  4. D
    r1−r22{{{r_1} - {r_2}} \over 2}2r1​−r2​​
View written solutionFree

Correct answer: B

Kirchhoff’s law has to be applied to the whole loop.

AIPMT 2006 Physics - Current Electricity Question 66 English Explanation

while i=2E(r1+r2+R)i = {{2E} \over {\left( {{r_1} + {r_2} + R} \right)}}i=(r1​+r2​+R)2E​

If through one section (here the first battery) has zero potential difference, current cannot flow. The question could have been modified.

The statement that when the circuit is closed, the potential difference across the first cell is zero implies that in a series circuit, one part cannot conduct current which is wrong. Kirchhoff’s law is violated.

Assuming that ir1 = E as given in the question paper, some students could have found that R = r1 – r2. They have to be given marks.

PreviousNext

More from Current Electricity

  • Kirchoff's first and second laws of electrical circuits are consequences of2006 · MCQ
  • Power dissipated across the 8 Ω resistor in the circuit shown here is 2 watt. The power dissipated in watt units across the 3 Ω resistor is Includes diagram2006 · MCQ
  • A 5-ampere fuse wire can withstand a maximum power of 1 watt in the circuit. The resistance of the fuse wire is2005 · MCQ
  • For the network shown in the figure the value of the current i is Includes diagram2005 · MCQ
  • Two batteries, one of emf 18 volts and internal resistance 2 Ω and the other of emf 12 volts and internal resistance 1 Ω, are connected as shown. The voltmeter V will record a reading of Includes diagram2005 · MCQ
  • When a wire of uniform cross-section a length l and resistance R is bent into a complete circle. resistance between any two of diametrically opposite points will be2005 · MCQ
  • Five equal resistances each of resistances R are connected as shown in the figure. A battery of V volts is connected between A and B. The current flowing in AFCEB will be Includes diagram2004 · MCQ
  • when three identical bulbs of 60 watt, 200 volt rating are connected in series to a 200 volt supply, the power drawn by them will be2004 · MCQ