Question

A coil of area 0:2 m2and total resistance 100 is rotated at a rate of 60 rev/s. Its axis ofrotation is perpendicular to a 0:5 T magnetic eld. How many turns are in the coil if energyis delivered to it at a maximum rate of 1420 W?

Answer 1

To solve this exercise it is necessary to apply the concepts given in the Faraday expressions and the induced voltage.

By definition the emf is given under the equation

`\epsilon =NBA\omega`

`\omega =`Angular Velocity

N = Number of Loops

B = Magnetic Field

A = Cross-Sectional Area.

At the same time we know that the rate of energy delivered is defined as,

`P = (\epsilon^2)/(R)`

`\epsilon = √(PR)`

Re-arrange the firs equation to find the number of loops and replacing the definition previously found we have,

`N = (√(PR))/(BA\omega)`

`N = (√(1420*100))/(0.5*0.2*(60*2\pi))`

`N = 10`

Therefore the number of turns in the coild if energy is delivered to it at a maximum rate of 1420W are 10 loops.