Transformers _ GCSE Physics

The video tutorial explains the function and types of transformers, focusing on step-up and step-down transformers used in the national grid. It describes their structure, working principle through electromagnetic induction, and the importance of AC current. The tutorial provides formulas for calculating potential differences and highlights the efficiency of transformers. It also introduces switch mode transformers used in electronic chargers, noting their high-frequency operation and low power consumption when idle.

What is the primary function of a step-up transformer?

• To convert AC to DC

• To store electrical energy

• To increase the voltage

• To decrease the voltage

In a step-down transformer, how does the number of turns in the primary coil compare to the secondary coil?

• Both coils have the same number of turns

• The primary coil has fewer turns

• The primary coil has more turns

• The secondary coil has more turns

How can you calculate the potential difference across the secondary coil of a transformer?

• By multiplying the turns ratio by the input voltage

• By dividing the input voltage by the turns ratio

• By subtracting the turns ratio from the input voltage

• By adding the input voltage to the turns ratio

What assumption can be made about the efficiency of transformers?

• They are almost 100% efficient

• They are 50% efficient

• They are 25% efficient

• They are 75% efficient

What is a key feature of switch mode transformers used in chargers?

• They operate at low frequencies

• They consume a lot of power when not in use

• They operate at high frequencies

• They are used to convert DC to AC