Question

When two 2Ω resistances are in parallel, the effective resistance is
(a) 2 Ω
(b) 4 Ω
(c) 1 Ω
(d) 0.5 Ω

Answer 1

(c) option is correct.

Answer 2

Given,

Two 2Ω resistances are connected in parallel.

To Find,

The effective resistance =?

Solution,

We can solve the question as follows:

It is given that two 2Ω resistances are connected in parallel. We have to find the equivalent resistance.

When two or more resistances are connected in parallel, the effective resistance is equal to the sum of the inverse of each individual resistance.

For example, if R1 and R2 are connected in parallel, then the effective resistance will be:
$\frac{1}{R_{Eff} }= \frac{1}{R_{1} } + \frac{1}{R_{2} }$

In the given question,

$R_{1} = 2\: Ohms$

$R_{2} = 2\: Ohms$

Substituting the values in the above formula,

$\frac{1}{R_{Eff} }= \frac{1}{2 } + \frac{1}{2 }$

$\frac{1}{R_{Eff} }= 1$

$R_{Eff} = 1\: Ohm$

Hence, the effective resistance is equal to 1 Ohm.