Important questions based on NCERT syllabus for Chapter 13 - Magnetic Effects of Electric Current:
Question-1: Name two safety measures commonly used in electric circuits and appliances. Explain one of the measures in brief.
Solution: 1. Earth wire is used to remove any leakage current from any metallic part of an appliance or an insulated wire.
2. Electric fuse has a high resistance and low melting point and disconnects the circuit in case a short circuit occurs.
3. Electric fuse is a safety device used in electric circuits to protect the circuit and appliances from damage due to overloading and short circuit. Fuse wire is made of a metal or an alloy of metals like lead, tin, aluminium and copper. Fuse wire is connected in series with the live wire.
Question-2: State the principle of an electric generator.
Solution: Electric Generator works on the principle of electromagnetic induction which obeys Fleming’s Right Hand Rule. When coil is moved inside a magnetic field, the strength of field at the location of the arms of coil changes due to change of distance from the magnets and a current is induced in the coil. The electric current is thus generated by electric generator.
Question-3: Give the factors that affect strength of magnetic field at a point due to a straight conductor carrying current.
Solution: Following factors affect the strength of magnetic field :
(i) Magnitude of electric current,
(ii) Perpendicular distance between that point and conductor
(iii) Permeability of the medium.