Two resistances R_1 and R_2 are connected in parallel. Their equivalent resistance is:

Correct option is A

Sol: The correct answer is (a) $$\frac{R_1.R_2}{R_1+R_2} ​$$

Solution:

When two resistances $$R_1$$ and $$R_2$$ are connected in parallel, the formula for their equivalent resistance $$R_{eq}$$ is:
​$$\frac{1}{R_{eq}}=\frac{1}{R_1}+\frac{1}{R_2}$$​​

$R$Find $$R_{eq}$$ :

​Take the reciprocal of each resistance:

​$$\frac{1}{R_{eq}}=\frac{1}{R_1}+\frac{1}{R_2}$$

​​Find the sum of the reciprocals:

$$\frac{1}{R_{eq}}$$​  =   $$\frac{R_1+R_2}{R_1.R_2} ​$$

​​Take the reciprocal of the result to find $$R_{eq}$$

​​$$R_{eq}$$ =  $$\frac{R_1.R_2}{R_1+R_2} ​$$

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