Question

The transformation ratio of a step up transformer is :

• A. greater than one
• B. less than one
• C. less than one and some times greater than one
• D. greater than one and some times less than one

Answer 1

The correct option is A greater than one

The transformation ratio of transformer is given by,

$K=\frac{N_2}{N_1}=\frac{E_2}{E_1}$

where $N_1,N_2$ are number of turns for primary and secondary coil and $E_1,E_2$ are their respective emf's.

and $K$ is the transformation ratio.

If $N_2>N_1$ i.e. $K>1$ then the transformer is called step-up transformer.

If $N_2<N_1$ i.e. $K<1$ then the transformer is called step-down transformer.

hence the transformation ratio of the step-up transformer is grater than one.