Find the maximum AC current flowing through the generator.

[driedupfish]

QUESTION 10***
A generator with output voltage ε(t) = εmax cos (ωt) is connected to the primary of a transformer. A resistor is connected to the transformer secondary. The transformer has an iron core with N1 turns on the primary and N2 turns on the secondary. Assume that the transformer is ideal and dissipates no energy.

Find the maximum AC current flowing through the generator.

http://online.physics.uiuc.edu/cgi/courses/shell/common/showme.pl?courses/phys212/oldexams/exam3/fa07/fig10b.gif

http://online.physics.uiuc.edu/cgi/courses/shell/common/showme.pl?courses/phys212/oldexams/exam3/fa07/fig10a.gif


V2 = (N2 / N1) V1. <--- equation for transformer

V2 is the voltage across the second coil, and V1 is the generator voltage, which is Emax.
So to solve for the max AC current, I divide V2 by R, which would yield choice A, but the answer is B, can someone explain what I did wrong?

 

[rl.bhat]

They have asked Imax in primary circuit.
V2 = (N2 / N1) V1.
Next input power = outputpower.
So V2 I2 = V1I1
I1 = (V2/V1)I2.. Substitute the values of V2/V1 and I2 to get the result.

 

[nlightner]

Your approach is correct, but there may be a mistake in your calculation. Let's break down the steps to find the maximum AC current flowing through the generator:

1. Use the equation for the transformer: V2 = (N2 / N1) V1
2. Substitute in the given values: V2 = (N2 / N1) Emax
3. Use Ohm's Law to find the current: I = V2 / R
4. Substitute in the resistance value: I = (N2 / N1) Emax / R
5. Simplify: I = (N2 / N1) (Emax / R)

So the correct answer should be A, as you initially thought. It's possible that you made an error in your calculation and got the wrong answer. Double check your work and see if you can find the mistake.