Question

An induction cooktop works on the principle of electromagnetic induction. Inside the cooktop there is a tightly wound metal coil. An alternating current flows through the coil and produces an invisible, high-frequency, alternating magnetic field all around it. When a vessel made of magnetic material is placed on the cooktop, the magnetic field produced by the coil penetrates the iron of the vessel and induces whirling electrical (eddy) currents inside the pan and makes it hot. There is no open flame used. Heat from the pan flows directly into the food or water inside it (by conduction) without heating up the area surrounding the cooktop. Unless there is a pan on the cooktop, no heat is produced. List any two advantages, with reasons, of cooking using an induction cooktop instead of a gas stove.

A coil is connected to a galvanometer as shown in the image below. The galvanometer shows a deflection to the right when the north pole of a magnet is moved towards the coil. State the deflection in the galvanometer when both the coil and the magnet are moved towards the right at the same speed. Give a reason for your answer.

A current clamp is an electrical device used to measure current in a conductor without making any physical contact with the conducting part of the conductor. The current clamp has jaws that clamp around the conductor as shown below. Some current clamps work on the principle of electromagnetic induction and hence can measure only alternating current. Give a reason why direct current cannot be measured by these current clamps.