Question

An induced current of \(2\)A flows through a coil. The resistance of the coil is \(10\Omega\). What is the change in magnetic flux associated with a coil in \(1\) ms ?

• A. \(2\times 10^{-3}wb\)
• B. \(2\times 10^{-2}wb\)
• C. \(22\times 10^{-2}wb\)
• D. \(22\times 10^{-4}wb\)

Hint:

Find the emf from Ohm's law, then use emf equals change in flux divided by time.

Answer 1

The Correct Option is B

Step 1: Understanding the Concept
The induced emf is \(\varepsilon=IR\) and also \(\varepsilon=\frac{\Delta\Phi}{\Delta t}\).

Step 2: Emf
\(\varepsilon=2\times10=20\) V

Step 3: Calculation
\(\Delta\Phi=\varepsilon\,\Delta t=20\times10^{-3}=2\times10^{-2}\) Wb

Step 4: Compare the options
This is option (B).

Final Answer:
The flux changes by 2 times 10 to the minus 2 weber. \[ \boxed{\text{(B) }2\times10^{-2}\,\text{Wb}} \]