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

Explain direct vision spectroscope, It is an instrument used to view pure s...

It is an instrument used to view pure spectrum. It makes dispersion without deviation with the help of n crown prisms and (n - 1½ flint prisms alternately arranged in a tabular str

State the law of conservation of electric charges, Q. State the law of cons...

Q. State the law of conservation of electric charges? The entirety charge in an isolated system always remains constant. For instance Uranium ( 92 U 238 ) can decay by emittin

.heart, name 3 things that will change how many times your heartbeats per d...

name 3 things that will change how many times your heartbeats per day..

Black body Radiation, When Temperature increases,intensity increases,but in...

When Temperature increases,intensity increases,but in some time intensity decreases,Why?

Kelvin effect, Thomson experiment; Kelvin effect (Sir W. Thomson [later Lor...

Thomson experiment; Kelvin effect (Sir W. Thomson [later Lord Kelvin]): While an electric current pass through a conductor whose ends are maintained at distinct temperatures,

How is quantum theory conceptual view explained, How is quantum theory conc...

How is quantum theory conceptual view explained? Quantum theory gives us with the rules and regulations of the small world. The quantum theory conceptual foundation is mysterio

Excitation energy and potential, When the electron is known energy from ext...

When the electron is known energy from external source, it goes to higher energy level. This process is called as excitation. The minimum energy needed to excite an atom is know

Financial records, Safe and Sound Ltd is a public company whose business is...

Safe and Sound Ltd is a public company whose business is the manufacture and sale of home security systems.  Only 100,000 shares have been issued: Kate Smith and her sister Sara

Fresenls diffraction, working and construction of fabry perot interferomete...

working and construction of fabry perot interferometer

Estimate the temperature of vapour pressure, The vapour pressure of a subst...

The vapour pressure of a substance at  20.0 o C is 38.1  kPa and its enthalpy of vaporisation is 49.6  kJ mol -1 . Estimate the temperature at which its vapour pressure is 80.0 k

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