Question

Several resistors 240 ohms each are connected in parallel across a 10 V battery. If the equivalent resistance of this combination is 20 ohms, how many resistors are being used here?

Answer 1

Required Answer:-

Hints given in the question:

• Resistors each of resistance 240 ohms.
• The combination is parallel.
• Equivalent resistance = 20 ohms$.$

We have to find the no. of resistors?

Here all the resistors are equal and the combination is a parallel one. Then, equivalent resistance (Rp) = R/n where R is the individual resistance and n is the no. of resistors.

Then,

⇒ Rp = R/n

⇒ 20 ohms = 240 ohms / n

⇒ n = 240 ohms / 20 ohms

⇒ n = 12

$\therefore$ The number of resistors used in the combination is 12 (Ans).

Answer 2

So here we have to find the number of resistors which are being used here. To find this let's take a formula - Rp = R/n

So,

20 = 240 ohms / n ( bringing 20 to the left )

n = 240 / 20

= 12

∴ The 12 number of resistors used here.