alternating-currents Question 41
Question: Q. 8. (i) Draw a labelled diagram of a step-down transformer. State the principle of its working.
(ii) Express the turn ratio in terms of voltages.
(iii) Find the ratio of primary and secondary currents in terms of turn ratio in an ideal transformer.
(iv) How much current is drawn by the primary of a transformer connected to
U [O. D. I, II, III 2016]
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Solution:
Ans. (i) Labelled diagram :
Principle :
When the current flowing through the primary coil changes, an emf is induced in the secondary coil due to the change in magnetic flux linked with it.
[Note : Give
(ii)
(iii) For an ideal transformer,
(iv) We have
$$ \begin{aligned} i_{p} V_{p} & =i_{s} \mathrm{~V}{s}=550 \mathrm{~W} \ V{p} & =220 \mathrm{~V} \ i_{p} & =\frac{550}{220}=\frac{5}{2}=2.5 \mathrm{~A} \end{aligned} $$
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