Question

In a step-down transformer, the transformation ratio is 0.1, current in primary is 10 mA. The current in

secondary is

• A. 10 Ma
• B. 1 Ma
• C. 1 Ma
• D. 0.1 A

Answer 1

Answer: (D)

0.1 A

Answer 2

We know that, the transformation of current or voltage from primary to secondary or vice-versa in an ideal transformer takes place according to transformation ratio. Since, it is a step-down transformer, the turns in secondary are smaller in number. Hence current in secondary must be larger. Therefore the secndary current must be $\frac{1}{0.1}$ times the primary current. Hence

$I_{s} = 10 \times 10mA = 100mA = 0.1amp$