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 weightlessness, Explain Weightlessness When can you feel weight...

Explain Weightlessness When can you feel weightless? There are two basic ways. You can be far enough away from all large objects in the universe that the force of gravity due t

What is potential difference , It is the difference among potential at two ...

It is the difference among potential at two points of a conductor. Please note that by potential(at a point A) ,we actually mean potential difference  among  point A and another

Energy transformation on a roller coaster, Energy Transformation on a Rolle...

Energy Transformation on a Roller Coaster A roller coaster ride is a thrilling experience that includes a wealth of physics. Part of the physics of a roller coaster is the phys

Expression for the magnetic induction, Derive a mathematical expression for...

Derive a mathematical expression for the magnetic induction at a point on the axial line of a bar magnet. Derive a mathematical expression for the magnetic induction at a point

Find out the significancy, In the movie The Shooter starring Mark Wahlber...

In the movie The Shooter starring Mark Wahlberg, it is claimed that coriolis forces need to be taken into consideration when taking a shot at a target 4 kilometres away. To test

Kinematics, Find the value of g by free fall method.

Find the value of g by free fall method.

How to make wedge, The wedge Make a wedge from a piece of wood and dri...

The wedge Make a wedge from a piece of wood and drive it inside a table leg or some other heavy object. View that the wedge is a double inclined plane

Image of this object formed in concave mirror-wave optics, The focal length...

The focal length of a concave mirror is 2 meters. An object is positioned 8 meters in front of the mirror. Where is the image of this object formed? Ans: The image of given ob

Polarisation, production and analysis of diffrent polarised light

production and analysis of diffrent polarised light

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