Question

An ideal transformer has 500 rums in the primary and 2500 in the secondary. The meters of the secondary are indicating 200 V, 8 A, under these conditions. What would the meters of the primary read?

• A. 100 V, 16 A
• B. 40 V, 40 A
• C. 160 V, 10 A
• D. 80 V, 20 A

Answer 1

Answer: (B)

Given, $ {{N}_{p}}=500 $ turns, $ {{N}_{s}}=2500,\,\,{{I}_{s}}=8\,\,A $ , $ {{e}_{s}}=200\,\,volt $ Transformation ratio $ (k)=\frac{{{N}_{s}}}{{{N}_{p}}}=\frac{{{e}_{s}}}{{{e}_{p}}}=\frac{{{I}_{p}}}{{{I}_{s}}} $ $ \therefore $ $ \frac{{{N}_{s}}}{{{N}_{p}}}=\frac{{{e}_{s}}}{{{e}_{p}}}\frac{2500}{500}=\frac{200}{{{e}_{p}}} $ $ \therefore $ $ {{e}_{p}}=40\,\,volt $ Again, $ \frac{{{N}_{s}}}{{{N}_{p}}}=\frac{{{I}_{p}}}{{{I}_{s}}} $ $ \frac{2500}{500}=\frac{{{I}_{p}}}{8} $ $ {{I}_{p}}=40\,\,A $