1On which principle is the working of a transformer based: electromagnetic induction, mutual induction, motor effect or lighting effect of current?
2Which is the transformer's formula: \( \frac{V_p}{V_s} = \frac{N_s}{N_p} \), \( \frac{V_s}{N_p} = \frac{N_s}{V_p} \), \( \frac{V_s}{V_p} = \frac{N_p}{N_s} \) or \( \frac{V_s}{N_s} = \frac{V_p}{N_p} \)?
3Differentiate between a step-up transformer and a step-down transformer.
4Give reason: the number of primary windings and secondary windings of a transformer are not the same.
5Give reason: transformers are used in mobile chargers.
6Electricity from a power station passes through transformer J, travels along high-voltage cables on tall towers, and passes through transformer K before reaching a consumer's house. Write the type of transformers J and K.
7Draw the block diagrams of the step-up transformer and step-down transformer and write two uses of each.
8To charge a laptop of 20 V, a charger with 550 primary turns is connected to an a.c. source of 220 V. Calculate the number of secondary windings of the charger.
9The number of secondary windings of a transformer used in a microwave oven is 10 times the number of windings in the primary coil. If it is connected to a source of 220 V, what is the secondary voltage obtained from the transformer?
10The ratio of the number of primary windings to secondary windings of a transformer is 22 : 1. If an adapter with that transformer is connected to an electric circuit having a potential difference of 220 V, calculate the output voltage so obtained.
11A transformer has 1000 turns in its primary coil and 50 turns in its secondary coil. What is its output voltage when connected to 220 V, and which type of transformer is it?
12In the router adapter calculation, the secondary turns came out as 27.27. Why is the answer taken as 28 turns?
13A transformer has 400 turns on each coil. What output voltage does it give from 220 V, and why is it no use for changing voltage?