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Question : 14
Total: 27
Using Kirchhoff's rules, calculate the current through the 40 Ω 20 Ω
OR
What is end error in a metre bridge? How is it overcome? The resistances in the two arms of the metre bridge areR = 5 Ω S
When the resistanceS 1.5 l 1 l 1 S
OR
What is end error in a metre bridge? How is it overcome? The resistances in the two arms of the metre bridge are
When the resistance
Solution:
(a) Writing two loop equations
(b) Calculation of currents through40 Ω 20 Ω
In loopA B C D A
+ 80 − 20 I 2 + 40 I 1 = 0
4 = I 2 − 2 I 1
In loop FCDEF
− 40 I 1 − 10 ( I 1 + I 2 ) + 40 = 0
− 50 I 1 − 10 I 2 + 40 = 0
5 I 1 + I 2 = 4
Solving these two equations
I 1 = 0 A
I 2 = 4 A
OR
End error, overcoming
Formula for metre bridge
Calculation of value ofS
The end error, in a metre bridge, is the error arising due to
(i) Ends of the wire not coinciding with the0 cm ∕ 100 cm
(ii) Presence of contact resistance at the joints of the meter bridge wire with the metallic strips.
It can be reduced/overcome by finding balance length with two interchanged positions ofR S S
For a metre bridge
=
For the two given conditions
=
=
Dividing the two equations
2 =
×
200 − 3 l 1 = 150 − 1.5 l 1
l 1 =
cm
Putting the value ofl 1
S = 10 Ω
(b) Calculation of currents through
In loop
In loop FCDEF
Solving these two equations
OR
End error, overcoming
Formula for metre bridge
Calculation of value of
The end error, in a metre bridge, is the error arising due to
(i) Ends of the wire not coinciding with the
(ii) Presence of contact resistance at the joints of the meter bridge wire with the metallic strips.
It can be reduced/overcome by finding balance length with two interchanged positions of
For a metre bridge
For the two given conditions
Dividing the two equations
Putting the value of
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