### Q.13:- A hot plate of an electric oven connected to a 220 V line has two resistance coils A and B, each of 24 Ω resistances, which may be used separately, in series, or in parallel. What are the currents in the three cases?

**Answer:-**

Supply voltage,

*V*= 220 VHere Resistance of one coil,

*R*=24 Ω(i) Coils are used separately

According to Ohm’s law, V=I

_{1}R_{1}*I*

_{1 }is the current flowing through the coil

*I*

_{1}=V/R

_{1}=220/24=9.166A

∴ current flow through the coil when used separately is 9.16 A.

(ii) Coils are connected in series

R

_{2}=24 Ω+24 Ω=48 ΩAccording to Ohm’s law

*I*

_{2}=V/R

_{2}=220/48=4.58A

the current flowing through the series circuit is 4.58A

(iii) Coils are connected in parallel

According to Ohm’s law

*I*

_{3}=V/R

_{3}=220/12=18.33A

the current flowing through the parallel circuit is 18.33A