CameraIcon
CameraIcon
SearchIcon
MyQuestionIcon


Question

The value of $$R$$ for which $$20\%$$ of the main current passes through galvanometer of resistance $$80\Omega$$ is
1349047_68bdf63e8fc742ec9b8ea6f2763a0a12.png


A
10Ω
loader
B
20Ω
loader
C
30Ω
loader
D
40Ω
loader

Solution

The correct option is C $$20\Omega$$
Given : 20% of the main current passes through the galvanometer of resistance 80Ω80Ω 

Solution :
Let the main current be "i"
Since the Galvanometer and resistance R are connected in parellal so both will have same potential diffrence "v"
Current through Galvanometer is 20% of i
using ohm's law we can write
 v=$$ \frac{20}{100}i\times$$80 $$ \Rightarrow$$ v=16i        Eq-(1)

Left current will go through resistor R that is 80% of i
using ohm's law in resistor R 
v=$$ \frac {80}{100}i \times$$R      $$ \Rightarrow $$   v=$$ \frac{4}{5}iR$$            Eq -(2)


From Eq 1 and Eq 2 we get
16i=$$ \frac{4}{5}$$iR

R=20 ohm
The Correct Opt: B


Physics

Suggest Corrections
thumbs-up
 
0


similar_icon
Similar questions
View More


similar_icon
People also searched for
View More



footer-image