Question

Two resistors R1 ohms and 12ohms are connected in parallel in a circuit if the resultant resistance in the circuit is 3ohms find the value of R

Answer 1

ans is 4ohm as in parallel combination
1/R1 +1/R2 =1/R equivalent

or simply we can say

R equivalent =R1×R2/R1+R2
Here R1 is R1 and R2 is =12 and R eq =3
R1×12/R1+12 =3
so 3R1 +36 =12R1
it gives 9R1 =36
so R1=4 ohm

Hope it help!

Answer 2

Answer:

Two resistors R1 ohms and 12ohms are connected in parallel in a circuit if the resultant resistance in the circuit is 3ohms the value of R is $6$Ω

Explanation:

• A resistor is  used to resist the current flow through  a circuit

• If two resistors with resistances $R_{1} ,R_{2}$ are connected in parallel in a circuit the effective resistance that appeared in the circuit is given by the formula

             $1/R_{eff} =1/R_{1} +1/R_{2}$

          ⇒$R_{eff} =\frac{R_{1} R_{2} }{R_{1} +R_{2} }$

from the question, we have given that

the value of a resistance $R_{2}=12$Ω

the effective resistance of the circuit $R_{eff} =3$ Ω

substitute the given values to get the resistance

⇒$3=\frac{R_{1}*12 }{R_{1} +12 }$

⇒$3*R_{1} +3*12 =12*R_{1}$

⇒

$36=9R_{1}\\ R_{1}=36/9=6$