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

Briefly explain working of michelsons interferometer, Q. Briefly explain wo...

Q. Briefly explain working of Michelsons Interferometer? Michelson designed an instrument for the measurement of wavelength of sodium light, thickness of thin film and for many

De-broglie wavelength, According to de-Broglie theory, the wavelength of de...

According to de-Broglie theory, the wavelength of de-Broglie wave is given by Where h = Plank's constant, m = Mass of the particle, v = Speed of the particle, E = Energy of

At what upward acceleration will the string break, A 10.0-kg object is held...

A 10.0-kg object is held up by a string that will break when the tension exceeds 1.00 x 10 2 N. At what upward acceleration will the string break?

Explain force, FORCE: "Force is that agency which causes a body to alte...

FORCE: "Force is that agency which causes a body to alter its state of motion or rest". It is denoted by F ?

The magnetic circuit, THE MAGNETIC CIRCUIT In an electric circuit, a cu...

THE MAGNETIC CIRCUIT In an electric circuit, a current is established due to the existence of an electromotive force. In the same way, in a magnetic circuit, a flux is establis

The algebra of dimensionality, Rule 1: In order to sum or subtract two phys...

Rule 1: In order to sum or subtract two physical quantities the quantities must have the similar dimension. The final physical quantity has the similar dimensions. Physical quantit

Conductors, Their resistivity is very low and temperature coefficient of re...

Their resistivity is very low and temperature coefficient of resistance is not constant. These are materials with unfilled or overlapping energy bands. Current carriers here are fr

Pesudo force, Ask questidefination and explanation of pesudo force on #Mini...

Ask questidefination and explanation of pesudo force on #Minimum 100 words accepted#

What is the radius of the electron circular path, An electron moves perpend...

An electron moves perpendicular to Earth's magnetic field with a speed of 1.78 x 10 6 m/s. If the strength of Earth's magnetic field is about 5.00 x 10 -5 T. what is the

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