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

What is the angular magnification of the telescope, Q. (a) A giant refract...

Q. (a) A giant refracting telescope at an observatory has an objective lens of focal length 15m. If an eyepiece of focal length 1.0 cm is used, what is the angular magnification o

Christmas carol, one of scrooges relatives visited him in the counting hous...

one of scrooges relatives visited him in the counting house. who was it and what did he want ........................... i couldnt found a subject with reading

Throttling process, In thermodynamics, the Joule-Thomson effect describes a...

In thermodynamics, the Joule-Thomson effect describes a process in which a fluid is forced through a valve or porous plug while kept insulated so that no heat is exchanged with the

Find the temperature of the gas?, In accrued model of a rotating diatomic m...

In accrued model of a rotating diatomic molecule of (Cl 2 ), the two Cl atoms are 2.00´ 10? -10  m apart and rotate about their center of mass with angular speed w = 2.00 ´10 12 ra

Define term practical optical fibre in short, Define term practical optical...

Define term practical optical fibre in short. Optical fibre: A practical optical fibre has in common three coaxial areas. The innermost area is the light guiding region term

Illustrate why does pilot tilt the outer wing of airplane, Q. Illustrate wh...

Q. Illustrate why does the pilot tilt the outer wing of the airplane inward while taking a turn? Answer:- Airplanes have two control surfaces implicated when turning the a

Integration, Integration Integration is an significant concept in mathe...

Integration Integration is an significant concept in mathematics and, together along with its inverse, differentiation, is one of the two major operations in calculus. Given a

Newton ring, Explain the formation of newton ring

Explain the formation of newton ring

Whether the molecular oscillators of the blackbody emitted, To develop the ...

To develop the correct mathematical explanation of the distribution of radiated energy of a blackbody with respect to wavelength for a given temperature. Planck found it essent

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