Question

A low-loss transformer has 230V applied to the primary and gives 4.6V in the secondary. The secondary is connected to a load, which draws 50A of current. The current (in ampere) in the primary is:
A) 0.1
B) 1.0
C) 10
D) 250

Answer 1

Hint: An electric current is defined as the net flow rate of the electric charge. The unit of current is Ampere. It is a stream of charged particles like ions or electrons that are moving through an electrical conductor.

Complete step by step solution:
Given data:
The primary voltage in the transformer, ${V_1} = 230V$
The secondary voltage in the transformer, ${V_2} = 4.6V$
 The secondary current, ${I_2} = 50A$
The primary current, ${I_1} = ?$
We know that power must be the same in the primary and the secondary transformers.
Also, power is given by the formula, $P = VI$
$ \Rightarrow {V_1}{I_1} = {V_2}{I_2}$
Substituting the values, we get
$ \Rightarrow 230 \times {I_1} = 4.6 \times 50$
$ \Rightarrow {I_1} = \dfrac{{4.6 \times 50}}{{230}} = 1A$
Thus the primary current, ${I_1} = 1A$

Hence the correct option is B.

Additional Information:
1. The voltage that is applied to the terminals of the primary winding is called a primary voltage transformer. In general, it is the side that takes the power and the side that delivers the power is the secondary.
2. In the case of a single-phase voltage transformer, the side with the higher voltage is considered as the primary.

Note: 1. An electrical device that transfers the electrical energy from one electrical circuit to another electrical circuit is called a transformer.
2. There are two types of current, Direct current and Alternating current. The electrons will flow in one direction with the direct current and the electrons will flow in both the direction with the alternating current.
3. Power is defined as the amount of energy transferred per unit of time. It is a scalar quantity. The unit of power is the watt. Power depends on the amount of work done and the time taken.