6 . A transformer draws 24 W of power from a 220 V power line, stepping the voltage down to 7.5 V. What is the equivalent resistance of the input circuit?

7.A circular loop of wire is in a spatially uniform magnetic field as shown. The magnetic field is directed into the screen and is perpendicular to the loop. What is the direction of the induced current in the loop, or is no current induced?

6 A transformer draws 24 W of power from a 220 V power line stepping the voltage down to 75 V What is the equivalent resistance of the input circuit 7A circular class=

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Answer:

  6.  2017 Ω, about 2000 Ω.

  7.  no current is induced unless the field is changing

Explanation:

6. The relationship between power, voltage, and resistance is ...

  P = V²/R

Rearranging gives

  R = V²/P = (220 volt)²/(24 watts) ≈ 2016.667 Ω

The closest answer choice is 2000 Ω.

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7. No current is induced in a stationary loop in a time-invariant magnetic field.

If something were changing, the direction of current induced would depend on whether the field is increasing or decreasing, and/or whether the loop is expanding or contracting.