Question

The primary coil of a transformer has 100 turns and the secondary coil has 200 turns. The primary coil is connected to a size AA battery that supplies a constant voltage of 1.5 volts. What is the measured voltage across the secondary coil?

• A. 3 volts
• B. 0.75 volts
• C. 0 volts
• D. 1.5 volts

Answer 1

The correct option is C 0 volts

The voltage drop across the secondary coil is 0.
A transformer works on the principle of electromagnetic induction. When the total magnetic flux through a coil changes an emf is induced in the coil. When the primary coil is connected to an AC supply, the change in the direction of current causes the direction of magnetic field lines to change. Due to this, the magnetic flux through the secondary coil changes, resulting in an induced emf. When DC supply is used, no such change occurs, hence no emf is induced.