# Worksheet: Electromagnetic Induction in Transformers

In this worksheet, we will practice calculating the change in the potential difference and current produced by a transformer.

**Q4: **

Which of the following is a suitable material for the core of a transformer?

- ACopper
- BAluminum
- CPolypropylene (plastic)
- DIron
- ECarbon

**Q6: **

A step-up transformer has turns on its secondary coil than on its primary coil, and, thus, a potential difference across the secondary coil than across the primary coil.

- Amore, higher
- Bmore, lower
- Cfewer, lower
- Dfewer, higher

**Q7: **

A 100% efficient transformer has 5 times as many turns on its secondary coil as it does on its primary. If the current through the primary coil is 20 A, what is the current through the secondary coil?

**Q9: **

A step-up transformer needs to change the potential difference of an alternating current from 50 V to 250 V. If the transformer has 100 turns on its primary coil, how many turns does it need to have on its secondary coil?

- A250 turns
- B125 turns
- C500 turns
- D100 turns
- E50 turns

**Q10: **

A step-up transformer has 8 times as many turns on its secondary coil as it does on its primary coil. If its input potential difference is 40 V, what is its output potential difference?

**Q11: **

What kind of current are transformers used with?

- ADirect current
- BBoth alternating current and direct current
- CAlternating current

**Q12: **

Which of the following electrical properties are changed by a efficient transformer?

- ABoth potential difference and current
- BCurrent only
- CPower only
- DPotential difference only
- EPotential difference and power