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

Calculate the index of refraction of air, A Rayleigh interferometer (as sho...

A Rayleigh interferometer (as shown in the figure below) can be used to measure the index of refraction of air. Two transparent tubes (T 1 and T 2 ) are placed behind two slits. O

Simple Harmonic Motion And Waves, Easy definition with explanation of FREQU...

Easy definition with explanation of FREQUENCY, WAVELENGTH, AMPLITUDE, DAMPED OSCILLATIONS.

Electricity., what should be the length of a nichrome wire of resistance 45...

what should be the length of a nichrome wire of resistance 45 ohms if the length of a similar wire is 60 cm and resistance is 25 ohms

Series combination of two capacitors, A 12 volt battery is associated acros...

A 12 volt battery is associated across a series combination of two capacitors C1 and C2. The capacitance of C2 is double that of C1.

Light absorbing materials in solar cells, All solar cells require a light a...

All solar cells require a light absorbing material contained within the cell structure to absorb photons and generate electrons via the photo voltaic effect. The materials used in

Insulation resistance, This is the virtue of a material resists flow of ele...

This is the virtue of a material resists flow of electric current. It should be as high as possible. When material is subjected to an electrical pressure then will always be a flow

What are the conditions to achieve the laser action, Q. What are the condit...

Q. What are the conditions to achieve the laser action? Conditions to achieve laser action (i) There should be an inverted population that is more atoms in the excited

Force and motion, to calculate average speed, divide distance by time...

to calculate average speed, divide distance by time?

Viscosity of liquid, How to determine the co efficient of viscosity of liqu...

How to determine the co efficient of viscosity of liquid by capillary flow method?

All about bernoulli, write bernoulli,s equation using pressure,energy,and h...

write bernoulli,s equation using pressure,energy,and heads.

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