A galvanometer of resistance, G is shunted by a resistance S ohm. To keep the main current in the circuit unchanged,the resistance to be put in series with the galvanometer is

$fraction numerator straight S squared over denominator left parenthesis straight S space plus straight G right parenthesis end fraction$
$fraction numerator SG over denominator left parenthesis straight S plus straight G right parenthesis end fraction$
$fraction numerator straight G squared over denominator left parenthesis straight S space plus straight G right parenthesis end fraction$
$fraction numerator straight G over denominator left parenthesis straight S plus straight G right parenthesis end fraction$

Solution

fraction numerator straight G squared over denominator left parenthesis straight S space plus straight G right parenthesis end fraction

Current will be unchanged if resistance remains same so

$straight G space equals space fraction numerator GS over denominator straight G space plus straight S end fraction space plus straight R straight R space equals space straight G space minus space fraction numerator GS over denominator straight G space plus straight S end fraction straight R space equals space fraction numerator straight G squared over denominator straight G space plus straight S end fraction$

Some More Questions From Moving Charges And Magnetism Chapter

Two moving coil meters, M₁ and M₂ have the following particulars:
R₁ = 10 Ω N₁ = 30,
A₁ = 3.6 x 10^–3 m², B₁ = 0.25 T
R₂ = 14 Ω; N₂ = 42,
A₂ = 1.8 x 10^–3 m², B₂ = 0.50 T
(The spring constants k are identical for the two meters).
Determine the ratio of (a) current sensitivity and (b) voltage sensitivity of M₂ and M_1.

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Moving Charges And Magnetism

Some More Questions From Moving Charges And Magnetism Chapter

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