Transformer 1

A laminated transformer core reduces the amount of energy that is wasted in the form of........

• solidifying

• flux

• heat

Why transformers work with A.C. current but not D.C.

• A.C current produces changing magnetic field.

• D.C current produces changing magnetic field.

• D.C current is weak

• A.C current is powerful

Which of the following does not change in a transformer?

• Voltage

• Current

• Power

• Frequency

Ratio of voltages is equal to ratio of _______________________.

• number of iron sheets in core

• number of coil

• number of turns in coil

• number of electromagnetic

The magnetic material for the core needs to be made of soft iron where its permeability is high

• to reduce eddy current loss

• to reduce hysteresis loss

• to avoid fringing in the core

• to reduce copper loss in the winding

Transformer works on which of the following principle

• Lenz’s Law

• Ampere's Law

• Faraday's Law of Electromagenetic Induction

• Fleming's Law

What is the material used for construction of transformer core?

• Aluminium

• Copper

• Iron

• Wood

Mutual inductance is

• interactions of one coils magnetic field on other coil as it induces a voltage in the adjacent coil

• Interactions of one coils magnetic field on other coil as it induces a current in the adjacent coil.

• Interactions of one coils magnetic field on other coil as it induces electrical energy in the adjacent coil

Induced voltage in primary and secondary winding depends on the following except for

• Resistor, R

• number of turns, N

• magnetic flux

• Frequency

In a transformer electrical power is transferred from primary to secondary

• Through air

• By magnetic flux

• Through insulation medium

• None of these