Magnetic Effects Of Electric Current Class 10 Notes Physics Science Chapter 13

What are Magnetic Effects of Electric Current?

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Color Coding of wires in a cable :

Wire Colour
Old Convention New Convention
Live (L) Red Brown
Neutral (N) Black Light Blue
Earth (E) Green Light Blue
  • The colour coding of wires help us to connect the switch, fuse, socket etc. through proper wire in house wiring.
  • The live wire is at a higher potential of 220V whereas the neutral wire is at the ground potential of 0V.
  • Overloading is the process of over heating of a wire due to excess current drawn by all the appliances than the permitted limit for that wire.
  • Short-circuiting is the process of over heating which may even cause fire when the live wire and the neutral wire come in contact due to defective or damaged wiring.
  • An electric fuse is a safety device which is used to limit the current in an electric circuit. It safeguards the circuits and the appliances connected in that circuit from being damaged.
  • An alloy of lead and tin is used as the material of the fuse wire because it has a low melting point (≅ 250°C) and its specific resistance is more than that of copper and aluminium.
  • The thickness of a fuse wire depends on its current rating. Higher the current rating, thicker is the fuse wire.
  • A fuse is always connected in series with the live wire before the appliance.
  • The fuse provided with an electric appliance to protect it against electric faults must be of current rating slightly higher than the maximum current that can be drawn by the appliance before being over heated.
  • A switch is an on-off device for current in a circuit. It is connected in the live wire.
  • To avoid the risk of electric shocks, the metal body of an electrical appliance is earthed. It is necessary to remove paint from the body part where earth connection is to be made.
  • In a three pin plug, the top pin is for earthing, the pin on the left is for live and the pin on the right is for neutral.
  • In a three pin socket, the upper hole is for earth connection, while the hole on the right side is for connection to the live wire and the hole on the left side is for connection to the neutral wire.
  • All electrical appliances such as bulbs, fans, sockets, etc. are connected in parallel across the live wire and the neutral wire.