### Discussion :: Series-Parallel Circuits - General Questions (Q.No.9)

Lavanya said: (Mar 4, 2011) | |

Explanation please? |

Ramu said: (Jun 10, 2011) | |

This will ans is correct but procedure is wrong. Wheat stone bridge Rx= (R2/R1) *R3. |

Anand said: (Jul 27, 2011) | |

(R1/R2)=(R3/R4),So R4=(R2/R1)*R3 |

Sai said: (Aug 5, 2011) | |

I agree with you anand. |

Tamilarasan said: (Aug 11, 2012) | |

In a wheatstone bridge the ratio is equal (i.e. R1*R2=R3*R4). So R2=R3*R4/R1. Sub the value. We will get the answer. |

Keerthi said: (Oct 28, 2013) | |

Here Rv means R1 or R3? |

Meenakshi said: (Feb 15, 2014) | |

Here Rv means variable resistance i.e., generally R3. Formula R4 = R2R3/R1, but here R4 is given, we have to fnd R1, so eqn becomes R1 = R2R3/R4. Therefore R1 = 720*10k/2.4K = 3000 ohms. |

Ankit Tiwari said: (May 27, 2014) | |

Normal formula apply here R1/R2 = R3/R4. |

Mahe said: (Jun 29, 2014) | |

In wheatstone bridge product of two opposite resistors is equal to the another product. Here R1 R2 and R3 wherever we can mention. So these kind of problems we need a circuit or figure. |

Nouman said: (Dec 3, 2014) | |

@Meenakshi : How do we find R1 ? when its already been given in the question. |

Ravi said: (May 9, 2015) | |

Formula: R1*R2 = R3*R4. Therefore R3 = (R1*R2)/R4. = (10k*720)/2.4 k. = 3000 ohms. |

Roopesh D M said: (Jun 17, 2015) | |

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: (Jun 25, 2015) | |

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: (Jun 27, 2015) | |

But in wheatstone bridge: R2/R1 = R4/R3. |

Parneet Kaur said: (Jul 9, 2015) | |

@Ankit Tiwari. Your formula is wrong. The correct formula is r1*r2=r3*r4. |

Megha said: (Jul 16, 2015) | |

Nice answer. |

Vijay said: (Oct 16, 2015) | |

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: (Jan 11, 2017) | |

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: (Oct 22, 2017) | |

No, the correct answer is 33.3kohm. |

Jagan said: (Apr 12, 2018) | |

I am not getting it. Please explain it. |

Mari Raj said: (Nov 11, 2018) | |

Unknown resister R3=(R1/R2)*R4. So, R3 = 33.3kohm. |

Hardiksinh said: (Mar 11, 2019) | |

Yes, R3 = 33.33, because the formula is R1R4=R2R3. Then R3= R1R4/R2. |

Darshil said: (Jul 29, 2019) | |

The correct formula is R1/R2 = R3/R4. So the answer comes 33.3kOhm. |

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