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Electrical Engineering - Series-Parallel Circuits - Discussion

Discussion Forum : Series-Parallel Circuits - General Questions (Q.No. 9)
Series-Parallel Circuits
9.
A certain Wheatstone bridge has the following resistor values: R1 = 10 k, R2 = 720 , and R4 = 2.4 k. The unknown resistance is
24
2.4
300
3,000
Answer: Option
Explanation:
No answer description is available. Let's discuss.
Discussion:
28 comments Page 2 of 3.
Ravi said:   1 decade ago
Formula: R1*R2 = R3*R4.

Therefore R3 = (R1*R2)/R4.

= (10k*720)/2.4 k.

= 3000 ohms.
ROOPESH D M said:   1 decade ago
Data is insufficient. Because we get different values of resistance depends on the bridge circuit.

We can take R1*R2 = R3*R4.

Or R1*R3 = R2*R4.

Or R1*R4 = R2*R4.

In each case we get different values, so without circuit we can't decide the unknown resistance value.
Chetan said:   1 decade ago
In wheatstone bridge product of two opposite resistors is equal to the another product.

So R1*R2=R3*R4,

R1, R2, R4 are given, we need to find R3.

R3 = R1*R2/R4 = 10K*720/2.4K = 3000.
Piya said:   1 decade ago
But in wheatstone bridge: R2/R1 = R4/R3.
Parneet kaur said:   1 decade ago
@Ankit Tiwari.

Your formula is wrong. The correct formula is r1*r2=r3*r4.
Megha said:   1 decade ago
Nice answer.
VIJAY said:   10 years ago
R1*R2 = R3*R4.

There for R3 = (R1*R2)/R4 720 ohm = 0.72 k ohm.

10k ohm*0.72k ohm/2.4k ohm.

3k ohm = 3k*1000.

Answer: 3000 ohm.
Puja said:   9 years ago
But, If we apply the formula R1/R2 = R3/R4 then answer is different from the answer of R1* R2= R3 * R4 formula. Please explain me again which method is right.
Aditya said:   8 years ago
No, the correct answer is 33.3kohm.
Jagan said:   7 years ago
I am not getting it. Please explain it.
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