How will u connect the three resistors? 4ohm, 6ohm and 12ohm so that the resultant resistance is 9ohm. draw a diagram? Plz answer if u know since I am practicing for my test and got stuck with this question!
Answers
Explanation :
You have to connect 4 ohm and 12 ohm in parallel combination and 6 ohm in series combination. If I connect then the resultant resistance is 9 ohm.
In parallel combination
→ 1/Rp = 1/R₁ + 1/R₂
Here, R₁ = 4 and R₂ = 12
→ 1/Rp = 1/4 + 1/12
→ 1/Rp = 3 + 1/12
→ 1/Rp = 4/12
→ 1/Rp = 1/3
→ Rp = 3 ohm
In series combination
→ Rs = R₁ + R₂
Here, R₁ = 6 and R₂ = 3
→ Rs = 6 + 3
→ Rs = 9 ohm
So, we have to connect like this.
Given :-
R1 = 4 Ω
R2 = 6 Ω
R3 = 12 Ω
To Find :-
How we connect
Solution :-
Resultant resistance = 9 Ω
We know that
Parallel combination = 1/R1 + 1/R2 + 1/R3 ... 1/Rn
=> 1/4 + 1/12
=> 3 + 1/12
=> 4/12
=> 1/3
=> 3 Ω
Now
Series combination = R1 + R2
=> 3 + 6
=> 9 Ω
Steps required
First you should connect R1 and R3 in parallel combination. Then use both and connect with R2.