Calculating unknown resistances by wheatstone bidge, Physics

Assignment Help:

Calculating unknown resistances

The current through the galvanometer (G) - a very sensitive ammeter, is reduced to zero by adjusting R4.  The bridge is then said to be balanced.  When the bridge is balanced, the voltage at A is equal to the voltage at B and no current flows between A and B.

424_wheat stone bridge.png

 

Hence       VR1             =       VR2

          therefore   I1 ´ R1           =       I2 ´ R2 ------------- (1)  (by Ohm's law)

          Also           VR3             =       VR4

          therefore   I1 ´ R3        =       I2 ´ R4 ------------- (2)

 

 

Dividing (1) by (2) 1368_Calculating unknown resistances.png

 

Therefore the unknown resistor  R3  = 1887_Calculating unknown resistances1.png    (all known values)

In calculations it is possible for any of the four resistors to be unknown.  However, provided that the bridge is balanced, the theory remains the same and all that is required is to transpose the equation to find the unknown 

 


Related Discussions:- Calculating unknown resistances by wheatstone bidge

Radiation hazards, Radiation Hazards: 1. They can injure our body cells...

Radiation Hazards: 1. They can injure our body cells. 2. Excessive radiation might be cause cancer. 3. Energetic radiation penetrates inside the body and can cause other

What do you mean by dispersion of light, What do you mean by dispersion of ...

What do you mean by dispersion of light? What is deviation given by a thin prism of angle 80 and refractive index is 1.5? For what angle of incidence, Snell's law is not working

How fast must a ring rotate, If a ring were constructed as knid of a space...

If a ring were constructed as knid of a space station. How fast must a 50.0-m-radius ring rotate to simulate Earth's gravity?

Properties of electromagnetic spectrum, Properties of  Electromagnetic spe...

Properties of  Electromagnetic spectrum: A spectrum can be divided into 3 regions. They are UV region, Visible region and IR region. Monochromatic light is a light which consi

Determine the angle of incidence for a ray of light, Determine the angle of...

Determine the angle of incidence for a ray of light to have minimum deviation of 39040' in equilateral prism.

Determine mass of car, A car is moving along a straight horizontal road at ...

A car is moving along a straight horizontal road at a speed of 20 meters per second.  The brakes are applied and a constant force of 5000 Newtons decelerates the car to a stop in 1

Precaution to minimize radiation danger, Precaution to minimize Radiation D...

Precaution to minimize Radiation Danger: 1. One should keep safe distance away from radiation emitting source. 2. The radiation from the reactor are shielded by thick concr

Evaluate the electric field, Question: Is it probable for the electric...

Question: Is it probable for the electric field to be zero in a region of space where the electric potential is not zero? Answer: Only if the electric potential has on

SEATBELTS, People believe that seatbelts are a MUST. But they think that th...

People believe that seatbelts are a MUST. But they think that they could increase the risk of other road users. Explain why it would be difficult to gather evidence for this idea..

Write Your Message!

Captcha
Free Assignment Quote

Assured A++ Grade

Get guaranteed satisfaction & time on delivery in every assignment order you paid with us! We ensure premium quality solution document along with free turntin report!

All rights reserved! Copyrights ©2019-2020 ExpertsMind IT Educational Pvt Ltd