A changing magnetic field makes a current: generators and transformers
Grade 11 Science Worksheet - Challenge Me
Circle the best answer, or write your answer on the line.
A line with 2 Ω of resistance carries 6000 W at 240 V. How much power is lost as heat in the line, Ari?
A line with 0.5 Ω of resistance carries 5000 W at 250 V. How much power is lost as heat in the line, Esme?
Why is electrical energy sent along power lines at very high voltage, Jun?
- Less current, less heat
- Higher voltage makes more energy
- High voltage travels faster
The same power is sent at 25 times the voltage. How does the heating loss in the line change, Luz?
- It drops to 1/625
- It rises 25 times
- It drops to 1/25
Milo says a step-up transformer gives out more energy than it takes in. Agree or disagree?
- Agree: more volts means more energy
- Disagree: it can't add energy
- Agree: the extra turns make energy
Noah says stepping up voltage with a transformer also steps up the current. Agree or disagree?
- Agree: current and voltage rise together
- Agree: current follows the turns
- Disagree: the current steps down
Pia says a magnet resting inside a coil makes a steady current. Agree or disagree?
- Agree: magnets push current along any wire
- Disagree: the field must change
- Agree: the coil stores it
How does a wireless charging pad charge a phone, Ren?
- Its changing field induces a current
- It sends charge through the air to the phone
- It heats the battery
A magnet falls slowly through a copper tube. Why, Tala?
- Induced currents push back
- Copper is magnetic and grabs it
- Air in the tube holds it up
Which way does an induced current act, Zee?
- With the change, speeding it up
- Against the change that caused it
- In no fixed way