14. Electric Current and its Effects Science class 7 in English Medium ncert book solutions Additional Questions

Additional Question:

Que: Mention the name of the two devices that work on the basis of magnetic effects of current.

Ans: The devices that work on the basis of magnetic effects of current are loudspeaker and electric bell.

Que: Name the device used days in place of eiectric fuses in electrical circuits.

Ans: The devices used in these days in place of electric fuse is MCB (Miniature Circuit Breaker).

Que: State the property of a conducting wire is utilised in making electric fuse. 

Ans: Electric fuse wire is made up of special material which has low melting point. As if high amount of current is passed, it melts to disconnect the electric circuit and prevent us from causing any damage.

Que: Name the type of mark foe which we should look at an electrical appliance before buying.

Ans: ISI mark is a mark for which we should look at an electrical appliance before buying.

Que: When does a circuit is said to be overloaded?

Ans: it is overloaded by connecting too many devices to it. When too many devices get connected, then a circuit is said to be overloaded.

Que: Why is an electric fuse required in all electrical appliance?

Ans: Electric fuse is required in all electrical appliances to prevent damage from excessive current flow and during short circuit.

Que: give the name any two electrical appliances in which electromagnets are used.

Ans: Electric fan and electrical motor are the electrical appliances in which electromagnets are used.

Que: The nails attract the pills. Comment?

Ans: When the current is passed through the wire wound on the nail, it behave as electromagnet. Due to this reason, the nails attract the pins.

Que: Name the scientist who discovered the magnetic effect of electric current.

Ans: The scientist who discovered the magnetic effect of electric current is Hans Christian Oersted.

Que: If the filament of the bulb is broken, would the circuit be complete? would the bulb still glow?

Ans: If the filament of the bulb is broken, the circuit will not be complete.

Que: Name some electric appliances where the heating effect of the electric current is used?

Ans: Some of the electric appliances where the heating effect of the electric current is used are electric heater, geyser, micro - oven, room heater, boiler etc.

Que: If the current through the coil stops flowing. will the coil remain an electromagents?

Ans: When the current through the coil stops flowing, the soil does not remain an electromagnet.