A hot plate of an electric oven connected to a `220 V` lines has two resistance coils `A and B`, each of `24 Omega` resistance, which may be used separately, in series or in parallel. What are the currents in the three cases ?

Explanation

Supply voltage, V=220 V
Resistance of one coil, `R= 24 Omega`
(i) Coils are used separately
According to Ohm's law,
`V_(1)I_(1)R_(1)`
Where,
`I_(1)` is the current flowing through the coil
`I_(1)=V//R_(1)=22=//24=9.166 A`
Therefore, 9.16 A current will flow will flow through the coil when used separately.
(ii) Coils are connected in series
Total resistance, `R_(2)=24 Omega+24 Omega=48 Omega`
According to Ohm's law, `V=I_(2)R_(2)`
Where,
`I_(1)` is current flowing through the series circuit
` I_(2)=V//R_(2)=22-//48=4.58 A`
Therefore, 4.58 A current will flow thrugh the circuit when the coils are connected in series.
(ii) Coils are connected in parallel
Total resistance, `R_(3)` is given as =
`1/(1/24+1/24)=24/2=12 Omega`
According to Ohm's law,
`V=O_(3)R_(3)`
Where,
`I_(3)` is the current flowing through the circuit `I_(3)=220//12=18.33` A
Therefore, 18.33 A current will through the circuit when coils are connected in parallel.