QCAA Physics Alternative Sequence Electromagnetism

Incorrect. A frequency of 1 rev/s would only produce an average EMF of $0.48$ V, which is insufficient.

Incorrect. A frequency of 3 rev/s would produce an average EMF of $1.44$ V, falling short of the required $6$ V.

Correct. Using the formula for average EMF $E_{avg} = 4NABf$, we find $f = 12.5$ rev/s. The minimum whole number of revolutions per second to achieve at least $6$ V is 13.

Incorrect. A frequency of 50 rev/s would produce an average EMF of $24$ V, which is much higher than the minimum required to reach $6$ V.

This order of magnitude is too large. It likely results from a math error with exponents or ignoring the coefficient of the charge during calculation.

Using the formula $V = \frac{W}{q}$, the potential difference is $\frac{1.5 \times 10^{-8} \text{ J}}{7 \times 10^{-6} \text{ C}} \approx 2.1 \times 10^{-3} \text{ V}$, which has an order of magnitude of $10^{-3} \text{ V}$.

This order of magnitude is too small and does not match the correct calculation of $V = \frac{W}{q}$.

This is the result of incorrectly multiplying the energy and charge ($W \times q \approx 10^{-13}$) instead of dividing them.