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

2014 · Q122
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. /2014 · Q122

Current Electricity question

2014 · Q122

NEETPhysicsCurrent ElectricityMCQ+4 / −1
A potentiometer circuit has been set up for finding the internal resistance of a given cell. The main battery, used across the potentiometer wire, has an emf of 2.0 V and a negligible internal resistance. The potentiometer wire itself is 4 m long. When the resistance R, connected across the given cell, has values of (i) infinity,    (ii) 9.5 Ω\OmegaΩ
the balancing lengths on the potentiometer wire are found to be 3 m and 2.85 m, respectively. The value of internal resistance of the cell is
  1. A
    0.25 Ω\OmegaΩ
  2. B
    0.95 Ω\OmegaΩ
  3. C
    0.5 Ω\OmegaΩ
  4. D
    0.75 Ω\OmegaΩ
View written solutionFree

Correct answer: C

Internal resistance of the cell,

r=(E−VV)R=(ℓ1−ℓ2ℓ2)Rr = \left( {{{E - V} \over V}} \right)R = \left( {{{{\ell _1} - {\ell _2}} \over {{\ell _2}}}} \right)Rr=(VE−V​)R=(ℓ2​ℓ1​−ℓ2​​)R

=(3−2.852.85)×(9.5)Ω=0.5Ω= \left( {{{3 - 2.85} \over {2.85}}} \right) \times \left( {9.5} \right)\Omega = 0.5\Omega=(2.853−2.85​)×(9.5)Ω=0.5Ω

PreviousNext

More from Current Electricity

  • Two cities are 150 km apart. Electric power is sent from one city to another city through copper wires. The fall of potential per km is 8 volt and the average resistance per km is 0.5 Ω. The power loss in the wire is2014 · MCQ
  • Two rods are joined end to end, as shown. Both have a cross-sectional area of 0.01 cm2. Each is 1 meter long. One rod is of copper with a resistivity of 1.7 × 10−6 ohm-centimeter, the other is of iron with a resistivity of… Includes diagram2013 · MCQ
  • A 12 cm wire is given a shape of a right angled triangle ABC having sides 3 cm, 4 cm and 5 cm as shown in the figure. The resistance between two ends (AB, BC, CA) of the respective sides are measuread one by one ratio Includes diagram2013 · MCQ
  • Ten identical cells connected in series are needed to heat a wire of length one meter and radius 'r' by 10oC in time 't'. How many cells will be required to heat the wire of length two meter of the same radius by the same temperature in…2013 · MCQ
  • The resistances of the four arms P, Q, R and S in a Wheatstone's bridge are 10 ohm, 30 ohm, 30 ohm and 90 ohm, respectively. The e.m.f. and internal resistance of the cell are 7 volt and 5 ohm respectively. If the galvanometer resistance…2013 · MCQ
  • The internal resistance of a 2.1 V cell which gives a current of 0.2 A through a resistance of 10 Ω is2013 · MCQ
  • A wire of resistance 4 Ω is stretched to twice its original length. The resistance of stretched wire would be2013 · MCQ
  • A cell having an emf ε and internal resistance r is connected across a variable external resistance R. As the resistance R is increased, the plot of potential difference V across R is given by2012 · MCQ