Read the following case and answer the following question:
Rohan wanted to learn how a simple electric circuit works. His teacher asked him to perform an activity using an electric cell, a cell holder, an incandescent lamp, a lamp holder, and four connecting wires. First, Rohan carefully removed about \(1\ cm\) of the plastic insulation from both ends of each wire to expose the metal. He then connected two wires to the cell holder and inserted the electric cell so that its negative terminal touched the spring inside the holder.
Next, he attached two wires to the lamp holder and fixed the incandescent lamp securely in place. Finally, he connected the free ends of the wires from the cell holder to the wires attached to the lamp holder. As soon as all the connections were completed properly, the lamp glowed. Rohan observed that when one wire became loose or disconnected, the lamp immediately stopped glowing. He concluded that a bulb glows only when electric current flows through a complete and closed circuit.
Next, he attached two wires to the lamp holder and fixed the incandescent lamp securely in place. Finally, he connected the free ends of the wires from the cell holder to the wires attached to the lamp holder. As soon as all the connections were completed properly, the lamp glowed. Rohan observed that when one wire became loose or disconnected, the lamp immediately stopped glowing. He concluded that a bulb glows only when electric current flows through a complete and closed circuit.
1. Why did Rohan remove the plastic covering from the ends of the wires?
2. Which component supplied electrical energy to the circuit?
3. Which energy transformation takes place inside the electric cell?
4. What is the main function of the connecting wires in the activity?