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 · Shift 0 · Q104
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. /JEE Main
  3. /Physics
  4. /Current Electricity
  5. /2006 · Shift 0 · Q104

Current Electricity question

2006 · Shift 0 · Q104

JEE MainPhysicsCurrent ElectricityMCQ+4 / −1
The resistance of bulb filmanet is 100Ω100\Omega100Ω at a temperature of 100∘C.{100^ \circ }C.100∘C. If its temperature coefficient of resistance be 0.0050.0050.005 per ∘C^ \circ C∘C, its resistance will become 200 Ω200\,\Omega200Ω at a temperature of
  1. A
    300∘C{300^ \circ }C300∘C
  2. B
    400∘C{400^ \circ }C400∘C
  3. C
    500∘C{500^ \circ }C500∘C
  4. D
    200∘C{200^ \circ }C200∘C
View written solutionFree

Correct answer: A: $300^\CIRC C$

  1. Use the linear relation for resistance with temperature

    If the resistance is known at temperature T1T_1T1​, then at temperature T2T_2T2​: R2=R1[1+α(T2−T1)]R_2 = R_1\left[1 + \alpha (T_2 - T_1)\right]R2​=R1​[1+α(T2​−T1​)]

  2. Given data

    • R1=100 ΩR_1 = 100\,\OmegaR1​=100Ω at T1=100∘CT_1 = 100^\circ CT1​=100∘C
    • R2=200 ΩR_2 = 200\,\OmegaR2​=200Ω
    • α=0.005 / ∘C\alpha = 0.005\,/\,^\circ Cα=0.005/∘C

  3. Substitute into the formula

    200=100[1+0.005(T2−100)]200 = 100\left[1 + 0.005(T_2 - 100)\right]200=100[1+0.005(T2​−100)]

  4. Simplify

    Divide both sides by 100100100: 2=1+0.005(T2−100)2 = 1 + 0.005(T_2 - 100)2=1+0.005(T2​−100)

    1=0.005(T2−100)1 = 0.005(T_2 - 100)1=0.005(T2​−100)

  5. Solve for T2T_2T2​

    T2−100=10.005=200T_2 - 100 = \frac{1}{0.005} = 200T2​−100=0.0051​=200

    T2=300∘CT_2 = 300^\circ CT2​=300∘C

  6. Check the options

    • A: 300∘C300^\circ C300∘C ✅
    • B: 400∘C400^\circ C400∘C
    • C: 500∘C500^\circ C500∘C
    • D: 200∘C200^\circ C200∘C

So, the correct answer is A.

  1. Comparison with stored answer

    The stored correct answer is B, but the calculation clearly gives A.

    Hence, the stored answer appears to be incorrect.

PreviousNext

More from Current Electricity

  • A thermocouple is made from two metals, Antimony and Bismuth. If one junction of the couple is kept hot and the other is kept cold, then, an electric current will2006 · MCQ
  • An electric bulb is rated 220 volt -100 watt. The power consumed by it when operated on 110 volt will be2006 · MCQ
  • In a Wheatstone's bridge, three resistance P,Q and R connected in the three arms and the fourth arm is formed by two resistances S1​ and S2​ connected in parallel. The condition for the bridge to be balanced will be2006 · MCQ
  • The current I drawn from the 5 volt source will be Includes diagram2006 · MCQ
  • Two sources of equal emf are connected to an external resistance R. The internal resistance of the two sources are R1​ and R2​(R1​>R1​). If the potential difference across the source having internal…2005 · MCQ
  • A moving coil galvanometer has 150 equal divisions. Its current sensitivity is 10- divisions per milliampere and voltage sensitivity is 2 divisions per millivolt. In order that each division reads 1 volt, the resistance in ohms…2005 · MCQ
  • The resistance of hot tungsten filament is about 10 times the cold resistance. What will be resistance of 100W and 200V lamp when not in use ?2005 · MCQ
  • An energy source will supply a constant current into the load if its internal resistance is2005 · MCQ