Question

What is the current in a parallel circuit which has two resistors (17.2 ohms and
22.4 ohms) and a power source of 6.0 volts?

A.
0.30 amps
B.
9.8 amps
C.
0.61 amps
D.
1.2 amps

Answer 1

Given:-

→ Resistance of 1st resistor = 17.2 Ω

→ Resistance of 2nd resistor = 22.4 Ω

→ Voltage = 6 volts

To find:-

→ Current in the parallel circuit.

Solution:-

When two resistances R₁ and R₂ are connected in parallel, then :-

⇒ 1/R = 1/R₁ + 1/R₂

⇒ 1/R = R₁ + R₂/R₁R₂

⇒ R = R₁R₂/R₁ + R₂

Substituting values, we get :-

⇒ R = 17.2×22.4/[17.2 + 22.4]

⇒ R = 385.28/39.6

⇒ R = 9.72 Ω

Now, we know that :-

V = iR

⇒ 6 = i×9.72

⇒ 6 = 9.72i

⇒ i = 6/8.72

⇒ i = 0.61 amp

Thus, current in the parallel circuit is 0.61 amp [Option.C]

Some Extra Information:-

If resistors are connected in such a way that the same potential difference gets applied to each of them, they are said to be 'connected in parallel'. The total current flowing into the combination is equal to the sum of the currents through the individual resistors.