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 3 Ω of resistance carries 12000 W at 6000 V. How much power is lost as heat in the line, Bo?
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?
- Higher voltage makes more energy
- Less current, less heat
- High voltage travels faster
What lowers the power-line voltage before it reaches homes, Kira?
- Longer, thinner wires along the way
- Step-up transformers
- Step-down transformers
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 drops to 1/25
- It rises 25 times
Milo says a step-up transformer gives out more energy than it takes in. Agree or disagree?
- Agree: the extra turns make energy
- Agree: more volts means more energy
- Disagree: it can't add energy
Noah says stepping up voltage with a transformer also steps up the current. Agree or disagree?
- Agree: current follows the turns
- Agree: current and voltage rise together
- Disagree: the current steps down
How does a wireless charging pad charge a phone, Ren?
- Its changing field induces a current
- It heats the battery
- It sends charge through the air to the phone
Which way does an induced current act, Zee?
- In no fixed way
- Against the change that caused it
- With the change, speeding it up