Question

In an ideal step down transformer, out of the following quantities, which quantity increases in the secondary coil?

• A. Power
• B. Voltage
• C. Current
• D. Frequency

Hint:

Voltage and current are inversely proportional in an ideal transformer. If it steps the voltage down, it inherently steps the current up. This is why high voltage is used for power transmission (to keep current low and minimize heat loss).

Answer 1

The Correct Option is C

Step 1: Understand the question.
We have an ideal step down transformer. We must pick which quantity becomes larger in the secondary coil out of power, voltage, current, and frequency.

Step 2: Check the power.
An ideal transformer wastes no energy. So the power going in equals the power coming out. Power stays the same, it does not increase.

Step 3: Check the frequency.
A transformer works by changing magnetic field, and it does not change how fast the AC swings. So the frequency stays the same in both coils.

Step 4: Check the voltage.
The words step down mean the transformer lowers the voltage. So the secondary voltage is smaller than the primary voltage. Voltage decreases, not increases.

Step 5: Check the current.
Since power $P = V \times I$ stays the same, if the voltage drops then the current must rise to keep the product the same:
\[ V_p I_p = V_s I_s \]
Because $V_s$ is smaller, $I_s$ must be larger. So the current increases.

Step 6: Write the answer.
The quantity that increases is the current. This matches option (3).
\[ \boxed{\text{Current increases in the secondary}} \]