Obtain an expression for the instantaneous value of the induced emf in an ac generator.

Explanation

To derive the expression for the instantaneous value of the induced emf in an AC generator, we can follow these steps:

### Step 1: Define the angle between the magnetic field and the coil
When a coil is rotated in a magnetic field with a constant angular speed (ω), the angle (θ) between the magnetic field and the area vector of the coil at any instant \( t \) can be expressed as:
\[ \theta = \omega t \]
**Hint:** Remember that angular speed is the rate of change of angle with respect to time.
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