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

In what direction does the particle move, If a negative charged particle en...

If a negative charged particle enters a magnetic field perpendicularly,then it follows a circular path.In what directn does the particle move---in clockwise or anticlockwise? So

What are mass defect and binding energy, What are mass defect and binding e...

What are mass defect and binding energy? How is mass defect related to binding energy? Describe the term ‘decay constant' for a radioactive substance. Reduce the relation betwee

Explain the term modulation, Explain the term modulation. Name three dissim...

Explain the term modulation. Name three dissimilar types of modulation used for a message signal using a sinusoidal continuous carrier wave. Describe the meaning of any one of thes

Particle function, Particle function: Protons The number of proton...

Particle function: Protons The number of protons in an atom determines the kind of material: Eg. Hydrogen 1 proton Helium 2 protons Lithium 3 protons B

Explain first law of newton, Explain Newton's First Law In 1665, at the...

Explain Newton's First Law In 1665, at the age of 23, Newton developed his famous Laws of Motion. They are commonly known as Newton's first, second and third law. Aside from th

Explain current carriers, The charged particles whose flow in a exact direc...

The charged particles whose flow in a exact direction constitutes the electric current are known as current carriers. In separate positions current carriers are dissimilar. (i)

Weber, Weber; Wb (after W. Weber, 1804-1891): The derived SI unit of m...

Weber; Wb (after W. Weber, 1804-1891): The derived SI unit of magnetic flux equivalent to the flux that, relating a circuit of one turn, generates in it an electromotive force

Inelastic scattering (raman''s effect), Under particular condition, light c...

Under particular condition, light can also suffer inelastic scattering from molecules in which it's wavelength changes.

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