(I) Here, `n_(p) = 20, n_(s) = 200, E_(p) = 220 V d.c., E_(s) = ?` Voltage acorss seconday will be zero, as transformer does not work on d.c. It is based on mutual induction.
(ii) Here, `E_(p) = 240 V, E_(s) = 24 v, I_(s) = (P_(0))/(E_(s)) = (24)/(24) = 1 A, I_(p) = ?`
From `(E_(s))/(E_(P)) = (I_(P))/(I_(s)) , I_(P) = (E_(s) xx I_(s))/(E_(P)) = (24 xx 1)/(240) = 0.1 A`
(iii) The relation `(E_(s))/(E_(P)) = (I_(P))/(I_(s))` show that for a step up transformer , `E_(s) gt E_(P) :. I_(P) gt I_(s)` or `I_(s) lt I_(P)`
i.e., when a transformer raises the a.c. voltage, alternating current reduces in the same ratio. For example,
if a.c. voltage becomes 100 times, output alternating current becomes `(1)/(100)` time.
In day to day life, we find that you cannot gain on all fronts, neither you will lose on all fronts. The gains and losses go together. Gain of one is loss of the other. In life, you have to weigh your priorities and act to meet them keeping in ming the above principle.