Question No$.1$

$25$ Marks $($ELO$2)$

$1.$ Define Principle of a Moving Coil galvanometer and explain the following terms in relation the the PMMC galvanometer.

a$)$ Deflection Torque $(2\mathrm{.}5)$

c$)$ Damping Torque $(25)$

b$)$ Control Torque $(2\mathrm{.}5)$

d$)$ Gritical Damping $(25)$

ii$.$

a$)$ A PMMC ammeter has the following specification: $\backslash (1\mathrm{.}5\backslash$times $10^\{-3\}\backslash$mathrm$\{$wb$\}/\backslash$mathrm$\{$m$\}^\{2\}\backslash ).$ Determine the no$.$ of turms required to produce a deflection of gsf whens a current $2$ mA flows through the coil.

b$)$ What is the value of series resistance to be used to extend $\text{'}0\text{'}$ to $2007$ range of $\backslash (20000\backslash$Omega $/\backslash$mathrm$\{$gais$\}\backslash )$ voltmeter to $0$ to $2000$ volt?

OR

iii. The pointer of a moving coil instrument gives full scale deflection of $20$ ma $.$ The gosential difference across the meter when carrying $20$ mA is $400$ mV $.$ The instrument to be used is $200$ sin sion full scale deflection and $1000$ V as voltmeter for full scale deflection.

a$)$ Find the shunt resistance required to achieve this.

b$)$ Find the series resistance to be comnected it$?$