Advertisements
Advertisements
Question
What will be the effect on the working of an electric bell if instead of a direct current an alternating current is used?
Advertisements
Solution
If electric bell is connected to a.c. instead of d.c. then bell will ring intermittently.
RELATED QUESTIONS
The diagram shows a coil wound around a U-shaped soft iron bar AB.
- What is the polarity induced at the ends A and B when the switch is pressed?
- Suggest one way to strengthen the magnetic field in the electromagnet.
- What will be the polarities at A and B if the direction of current is reversed in the circuit?
State two ways of magnetising an iron piece?
Name two factors on which the strength of magnetic field of an electromagnet depends and state how does it depend on the factors stated by you.
Name the material used for making the armature of an electric bell. Give a reason for your answer.
Describe briefly one way of producing an induced current in a coil. State one factor that determines the magnitude of induced e.m.f.
State the purpose of the iron core.
State the condition when an electric charge can give rise to a magnetic field.
State three factors which govern the speed of rotation of an electric motor.
State the factors that can increase the speed of rotation of the coil in a D.C. motor.
State the principle of a D. C. motor.
