Question

1. A piece of wire of resistance R is cut into five equal parts. These parts are then connected in
parallel. If the equivalent resistance of this combination is R', then the ratio R/R' is?
2. An electric bulb is rated as 220 V and 100 W. When it is operated on 110 V find the consumed
power
3. Two conducting wires of the same material and of equal lengths and equal diameters are first
connect series and then parallel in an electric circuit. Find the ratio of heat produced in series and
parallel combination.
4. An electric iron of resistance 20 n takes a current of 5 A. Calculate the heat developed in 30
seconds.

Answer 1

Answer:

1) when connected in parallel ,resistance=(1÷R)×5

resistance=R÷5

thus R÷R'=5