Fleming’s right hand rule 10th
Hold the thumb, the fore finger and the middle finger of right hand at right angles
to each other. If the fore finger is in the direction of magnetic field and the
thumb points in the direction of motion of conductor, then the direction of
induced current is indicated by middle finger.
Alternate Current (A. C.) : The current which reverses its direction periodically.
A.C. can be transmitted over long distance without much loss of energy.
A.C. cannot be stored.
Direct Current (D. C.) : The current which does not reverse its direction.
D.C. can be stored.
Loss of energy during transmission over long distance is high.
Sources of D. C. : Cell, Battery, Storage cells.
Domestic Electric Circuits
There are three kinds of wires used :
(i) Live wire (positive) with red insulation cover.
(ii) Neutral wire (negative) with black insulation cover.
(iii)Earth wire with green insulation cover.
e The potential difference between live and neutral wire in India is 220 V.
° Pole > Main supply > Fuse —> Electricity meter > Distribution box > To
Short Circuit : When live wire comes in direct contact with neutral wire accidently.
- Resistance of circuit becomes low.
- Can result in overloading.
Overloading : When current drawn is more than current carrying capacity of a
conductor, it results in overloading.
Causes of overloading :
(i) Accidental hike in voltage supply.
(ii) Use of more than one appliance in a single socket.
Safety devices :
(i) Electric fuse
(ii) Earth wire
(iii)MCB (Miniature Circuit Breaker)