Physics · Current Electricity

JEE Main 2024 — 29 January, Shift 1 — Question 31

The electric current through a wire varies with time as I=I0+βI=I_{0}+\beta t. where I0=20 AI_{0}=20 \mathrm{~A} and β=3 A/s\beta=3 \mathrm{~A} / \mathrm{s}. The amount of electric charge crossed through a section of the wire in 20 s is :

  1. Option A:

    80 C

  2. Option B:

    1000 C

    Correct
  3. Option C:

    800 C

  4. Option D:

    1600 C

Answer: B

Step-by-step solution

Given that Current I=I0+βtI=I_{0}+\beta t

I0=20 A\mathrm{I}_{0}=20 \mathrm{~A}

β=3 A/s\beta=3 \mathrm{~A} / \mathrm{s}

I=20+3t\mathrm{I}=20+3 \mathrm{t}

dqdt=20+3t\frac{d q}{d t}=20+3 t

∫0qdq=∫020(20+3t)dt\int_{0}^{q} d q=\int_{0}^{20}(20+3 t) d t

q=∫02020dt+∫0203tdt\mathrm{q}=\int_{0}^{20} 20 \mathrm{dt}+\int_{0}^{20} 3 t d t

q=[20t+3t22]020=1000Cq=\left[20 t+\frac{3 \mathrm{t}^{2}}{2}\right]_{0}^{20}=1000 \mathrm{C}

Answer key and solution verified before publishing.

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Exam
JEE Main 2024
Subject
Physics
Chapter
Current Electricity
Topic
Current in Conductors, Drift Speed, Resistivity and Relaxation Time
The electric current through a wire varies with time as I=I 0 +β t.… | JEE Main 2024 PYQ with Solution · DhiX AI