Get Answers to all your Questions

header-bg qa

 The galvanometer deflection , when key K1 is closed but K2 is open, equals \theta _{0} (see figure). On closing K2 also and adjusting R2 to 5 \Omega , the deflection in galvanometer becomes \frac{\theta _{0}}{5} . The resistance of the galvanometer is then , given by [ Neglect the internal resistance of battery ] :

  • Option 1)

     5 \Omega

  • Option 2)

     12 \Omega

  • Option 3)

     25 \Omega

  • Option 4)

     22 \Omega

Answers (1)

best_answer

 

Equivalent resistance -

\frac{Gs}{G+s}

- wherein

G- Galvanometer resistance

s-  Shunt resistance

Case 1

ig=\frac{E}{220+R_{g}}=c\Theta _{0}\, \, \, \, \, \, (1)

Case 2

ig=\left ( \frac{E}{220+\frac{5R_{g}}{5+R_{g}}} \right )\frac{5}{R_{g}+5}=\frac{c\Theta _{0}}{5}\, \, \, \, \, \, (2)

\left ( 1 \right )/(2)

\Rightarrow \frac{225R_{g}+1100}{1100+5R_{g}}=5

\Rightarrow R_{g}=22\Omega


Option 1)

 5 \Omega

Option 2)

 12 \Omega

Option 3)

 25 \Omega

Option 4)

 22 \Omega

Posted by

admin

View full answer

JEE Main high-scoring chapters and topics

Study 40% syllabus and score up to 100% marks in JEE