Question

The transformation ratio of a step-up transformer is

• A. 1
• B. Greater than 1
• C. Less than 1
• D. The ratio greater or less than depends on 1 on other factors

Answer 1

The correct option is B

Greater than 1

The explanation for the correct option:

In the case of option B,

The transformation ratio of the transformer is given by,
$K=\frac{N_2}{N_1}=\frac{E_2}{E_1}$
Where,

K is the voltage transformation ratio.

N₁ and N₂ are the number of turns for the primary and secondary coil respectively.

E₁ and E₂ are their respective emf’s respectively.

K is referred to as the voltage transformation ratio, which is a constant.

If $N_2>N_1$, $K>1$ the output voltage is more than the input voltage. Hence it is referred to as a step-up transformer.

Hence, The transformation ratio of a step-up transformer is greater than 1.

The explanation for the incorrect options.

1. If $N_2<N_1$, $K<1$the output voltage is less than the input voltage. Hence, it is referred to as a step-down transformer.
2. If $N_2=N_1,K=1$ there is no voltage change, the transformer is called an isolation transformer
3. The ratio depends only on the number of turns of the coil.

Therefore, the correct option is B.