How Does a Transformer Change Voltage and Current?

What happens to the current when a transformer changes the voltage from 120 V to 12000 V?

(a) Stepped up by a factor of 100

(b) Stepped down by a factor of 100

(c) Neither stepped up nor stepped down

Answer:

The current delivered by the wall socket is stepped down by a factor of 100.

A transformer changes the 120-V at a wall socket to 12000 V. The current delivered by the wall socket is:

A transformer changes the 120-V at a wall socket to 12000 V. The current delivered by the wall socket is:

To determine the effect on the current, we need to consider the transformer's voltage step-up factor. The voltage step-up factor can be calculated as follows:

Voltage step-up factor = Secondary voltage (output voltage) / Primary voltage (input voltage)

In this case, the primary voltage is 120 V, and the secondary voltage is 12000 V. Therefore, the voltage step-up factor is:

Voltage step-up factor = 12000 V / 120 V = 100

Now, transformers follow the principle of power conservation, which means the input power is equal to the output power (ignoring energy losses). The power equation is:

Power (P) = Voltage (V) × Current (I)

Since input power equals output power, we have:

Primary voltage × Primary current = Secondary voltage × Secondary current

We can rearrange this equation to find the relationship between primary and secondary current:

Primary current / Secondary current = Secondary voltage / Primary voltage

Plugging in the values:

Primary current / Secondary current = 100

This means that the primary current (current delivered by the wall socket) is 100 times larger than the secondary current.

Therefore, the correct answer is:

(b) The current delivered by the wall socket is stepped down by a factor of 100.

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