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

Describe features of wave motion , a) It is a sort of disturbance which goe...

a) It is a sort of disturbance which goes by a medium. b) Material phase is necessary for the propagation of mechanical waves. c) When a wave motion goes by a phase, molecule

Explain local electric field, Local electric field : It is the sum of the e...

Local electric field : It is the sum of the electric field from external sources and the field of the dipoles within the specimen. It is an idealized field calculated under particu

Dimension, dimension of electric current

dimension of electric current

Making a shadow stick, Making a shadow stick In an open space on the sc...

Making a shadow stick In an open space on the school ground drive a 130 cm stick into the ground and let the children stay a record of the length of the shadow, calculated two

Determine the volume flow rate, Water flows from a large tank through a lar...

Water flows from a large tank through a large pipe that splits into two smaller pipes as shown in Figure. If viscous effects are negligible (no head loss), determine the volume flo

Searle''s vibration magnetometer, how to find magnetic moment and the princ...

how to find magnetic moment and the principle behind the magnetometer?

Calculate uniform magnetic field, The greatest induced EMF will happen in a...

The greatest induced EMF will happen in a straight wire moving at constant speed by a uniform magnetic field. when the angle among the direction of the wire's motion and the di

Explain the formula of the stefan law, Explain the formula of the Stefan la...

Explain the formula of the Stefan law. STEFAN'S LAW: P = σ AT 4 Here: P = Power radiated into W (J/s) σ = Stefan's Constant 5.67 x 10 -8 W m -2 K -4 A = Su

The monkey and zookeeper- vectors and projectiles, The Monkey and Zookeeper...

The Monkey and Zookeeper There is an attractive monkey down at the zoo. The monkey spends most of its day execution from a limb of a tree. The zookeeper feeds the monkey throug

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