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

Isolated magnetic poles, Isolated magnetic poles do not exist'. explain? ...

Isolated magnetic poles do not exist'. explain? A. 1. If a bar magnet is cut into smaller and smaller pieces eventually ending with the smallest possible piece, this smallest

Pressure, A base of rectangular vessel measures 10cm x 8cm.

A base of rectangular vessel measures 10cm x 8cm.

Digital metimeter , Digital multimeters: Digital multimeters offer a nu...

Digital multimeters: Digital multimeters offer a number of significant advantages when compared with their more humble analogue counterparts.  The display fitted to a digital m

Searle''s apparatus, why metallic frame used in searles apparatus

why metallic frame used in searles apparatus

Explain about the V-i characteristics of constant voltage, Draw and explain...

Draw and explain V-I characteristics of constant voltage and constant current sources. Ans: V-I Characteristics of Constant Voltage Source: A voltage source that has very low

Optics, Describe the formation of Newton''s rings.

Describe the formation of Newton''s rings.

Experiments based on screw gauge, Screw gauge works on the rule of screw. ...

Screw gauge works on the rule of screw. It has a linear scale called as the main scale, and another scale called as the circular scale. The circular scale can be moved by a head sc

Define about the heat loss, Define about the Heat Loss? An immersion h...

Define about the Heat Loss? An immersion heater of power J=500 W can be used to heat water in a bowl. After 2 minutes the temperature enhance from T 1 =85 o C to T 2 =90°C. Th

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