Q99 / 180 · AIIMS 2007 · Physics
With the decrease of current in the primary coil from 2 amperes to zero value in \(0.01 \mathrm{~s}\) the emf generated in the secondary coil is 1000 volts. The mutual inductance of the two coils is
- A\(1.25 \mathrm{~H}\)
- B\(2.50 \mathrm{~H}\)
- Correct answerC\(5.00 \mathrm{~H}\)
- D\(10.00 \mathrm{~H}\)
Solution
Induced \(\operatorname{emf} \varepsilon=\frac{-M d I_P}{d t}\)
Where \(M\) is the mutual inductance of two coils and \(\frac{d I_P}{d t}\) is the rate of change of current in the primary.
\(\begin{aligned}
& \therefore \quad 1000 \mathrm{~V}=\frac{-M(0 \mathrm{~A}-2 \mathrm{~A})}{0.01 \mathrm{~s}} \\
& \text { or } M=\frac{(1000 \mathrm{~V})(0.01 \mathrm{~s})}{(2 \mathrm{~A})}=5 \mathrm{H} .
\end{aligned}\)
Hence, the correct answer is option: 'C'.