Show with the aid of a diagram how a wire is wound on a U-shaped piece of soft iron in order to make it an electromagnet. Complete the circuit diagram and label the poles of the electromagnet. Open Answer »
You are required to make an electromagnet from a soft iron bar by using a cell, an insulated coil of copper wire and a switch. (a) Draw a circuit diagram to represent the process. (b) Label the poles of the electromagnet. Open Answer »
How is an electromagnet made? Name two factors on which the strength of the magnetic field of an electromagnet depends. Open Answer »
Name the material used for making the armature of an electric bell. Give a reason for your answer. Open Answer »
How is the working of an electric bell affected, if alternating current is used instead of direct current? Open Answer »
Figure shows a coil wound around a soft iron bar XY. (a) State the polarity at the end X and Y as the switch is pressed. (b) Suggest one way of increasing the strength of the electromagnet so formed. Open Answer »
