Question

AC generator is a device based on electromagnetic induction used to convert mechanical energy into electrical energy. 

1. Draw a graph showing variation of induced emf over a cycle. Also indicate peak value of emf.

2. How peak value of emf is related to its rms value?

3. A rectangular wire loop of side 4 cm × 6 cm has 50 turns uniformly from 0.1 Tesla to 0.3 Tesla in 6 × 10^-2 second. Calculate induced emf in the coil.

Answer 1

2. Erms = \(\frac{E_0}{\sqrt{2}}\)

3.  \(\varepsilon=-\frac{d\phi}{dt}=-\frac{(\phi_1-\phi_2)}{t}\)

and Φ = BAN 

Φ₁ = 0.1 × (24 × 10^-4) × 50 

= 120 × 10^-4 wb 

Φ₂ = 0.3 × (24 × 10^-4) × 50 

= 360 × 10^-4 wb

\(\varepsilon=\Big(\frac{120\times10^{-4}-360\times10^{-4}}{6\times 10^{-2}}\Big)\)

= 40 × 10^-2 V