Q93 / 120 · VITEEE 2011 · Physics

Ina magnetic field of $0.05 \mathrm{~T}$, area of a coil changes from $101 \mathrm{~cm}^{2}$ to $100 \mathrm{~cm}^{2}$ without changing the resistance which is $2 \Omega$. The amount of charge that flow during this period is

  • Correct answer
    A
    $2.5 \times 10^{-6} \mathrm{C}$
  • B
    $2 \times 10^{-6} \mathrm{C}$
  • C
    $10^{-6} \mathrm{C}$
  • D
    $8 \times 10^{-6} \mathrm{C}$

Solution

Magnetic Flux, $\phi=B \cdot A$ Change in flux, $\mathrm{d} \phi=B \cdot d A$ $=0.05(101-100) \times 10^{-4}$ $=5 \times 10^{-6} \mathrm{~Wb}$ Charge dQ $=\frac{d \phi}{R}$ $=\frac{5 \times 10^{-6}}{2}=2.5 \times 10^{-6} \mathrm{C}$

Hence, the correct answer is option: 'A'.

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