Question

Two resistor, one of 15ohm and other 10 ohm are connected in parallel, this combination is connected in series with a 24 ohm resistor, And A 21 volt battery. the current in the 10 ohm resistor is?

0.80 A
0.16 A
0.24 A
0.40 A

Answer 1

Please find the answer attached and feel free to ask any doubts.

Answer 2

Total Resistance across the Parallel combination,

1/Re = 1/R₁ + 1/R₂

∴ 1/Re = 5/30

∴ Re = 6

Now, Total Resistance = 6 + 24 = 30

Using Ohm's law,

I = V/R = 21/30

= 0.7 A.

Means this much current will Reach in Parallel combination and also in the series part.

Now, Potential given to 24 Ohm resistor, = 24 × 0.7 = 16.8 V.

Now, Potential given to Parallel combination = 21 - 16.8 = 4.2 V.

Now, This much Potential will Reach both the Resistor of 15 Ω and 10 Ω.

Therefore Using Ohm's law,

V = I × R

4.2 = I × 10

∴ I = 0.42 A

Hence, Correct answer is Option (d).

Hope it helps.