Transformers

Derive an expression for e.m.f. and current in terms of turns ratio

Mention various energy losses in transformer device

State the principle of a step-up transformer. Explain, with the help of a labeled diagram, its working ?

Magnetic flux Φ in weber in a closed circuit of resistance 10Ω varies with time Φ (sec) as Φ = 6t² - 5t + 1. The magnitude of induced current at t = 0.25s is ______.

A transformer lowers e.m.f. 220 V to 12 volts. If the number of turns in primary are 8800, how many turns are in secondary coil?

Read the following paragraph and answer the question:

Long distance power transmissions

The large-scale transmission and distribution of electrical energy over long distances is done with the use of transformers. The voltage output of the generator is stepped up. It is then transmitted over long distances to an area sub-station near the consumers. There the voltage is stepped down. It is further stepped down at distributing sub-stations and utility poles before a power supply of 240 V reaches our homes.

A power transmission line feeds input power at 2300 V to a step down transformer with its primary windings having 4000 turns. The number of turns in the secondary in order to get output power at 230 V are ______.

A 60 W load is connected to the secondary of a transformer whose primary draws line voltage. If a current of 0.54 A flows in the load, what is the current in the primary coil? Comment on the type of transformer being used.