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KCET · Physics · Electromagnetic Induction

The magnetic flux linked with a coil varies as \( \phi=3 t^{2}+4 t+9 . \) The magnitude of the emf
induced at \( t=2 \) seconds is

  1. A \( 8 \mathrm{~V} \)
  2. B \( 16 \mathrm{~V} \)
  3. C \( 32 \mathrm{~V} \)
  4. D \( 64 \mathrm{~V} \)
Verified Solution

Answer & Solution

Correct Answer

(B) \( 16 \mathrm{~V} \)

Step-by-step Solution

Detailed explanation

Given, magnetic flux, \( \phi=3 t^{2}+4 t+9 ; t=2 s \)
Since, emf induced \( =\frac{d \phi}{d t} \)
Therefore, emf induced at \( t=2=\left.\frac{d \phi}{d t}\right|_{t=2} \)
Now, \( \frac{d \phi}{d t}=6 t+4 \)
\( \left.\Rightarrow \frac{d \phi}{d t}\right|_{t=2}=6 \times 2+4=12+4=16 \)
Thus, emf induced \( =16 \mathrm{~V} \)