1)

An ideal transformer converts 200 V  AC to 3.3 kV  AC to transmit a power of 4.4 kW .If primary coil has 600 turns, then alternating current in the secondary coil is 


A) $\frac{1}{3}$ A

B) $\frac{4}{3}$ A

C) $\frac{5}{3}$ A

D) $\frac{7}{3}$ A

Answer:

Option B

Explanation:

 Given, input voltage (Vp) =220 V

 Output voltage (Vs) = 3.3 x 103 V

 Power (P) = 4.4 kW = 4.4 x 103 W

 Number of turns in primary coil = 600

 We know that,

   $P= V_{p}\times I_{p} \Rightarrow I_{p}=\frac{P}{V_{p}} or I_{p}=\frac{4.4\times 10^{3}}{220}=20A$

 For an ideal transformer,

$\frac{V_{s}}{V_{p}}=\frac{I_{p}}{I_{s}}$

$I_{s}=I_{p}\times\frac{V_{p}}{V_{s}}$

$I_{s}=\frac{20\times220}{3.3 \times 10^{3}}$

 or  $I_{s}=\frac{44}{33}=\frac{4}{3}A$