When a $12\,\Omega$ resistor is connected in parallel with a moving coil galvanometer,its deflection reduces from $50$ divisions to $10$ divisions. The resistance of the galvanometer is ............. $\Omega$.

$A$ galvanometer with its coil resistance $25\,\Omega$ requires a current of $1\,mA$ for its full-scale deflection. In order to construct an ammeter to read up to a current of $2\,A$,the approximate value of the shunt resistance should be:

Two identical moving coil galvanometers have $10 \Omega$ resistance and full scale deflection at $2 \mu A$ current. One of them is converted into a voltmeter of $100 \text{ mV}$ full scale reading and the other into an ammeter of $1 \text{ mA}$ full scale current using appropriate resistors. These are then used to measure the voltage and current in the Ohm's law experiment with $R = 1000 \Omega$ resistor by using an ideal cell. Which of the following statement$(s)$ is/are correct?
$(1)$ The measured value of $R$ will be $980.2 \Omega$.
$(2)$ The resistance of the voltmeter will be $50 \text{ k} \Omega$.
$(3)$ The resistance of the ammeter will be $0.02 \Omega$ (rounded off to the $2^{\text{nd}}$ decimal place).
$(4)$ If the ideal cell is replaced by a cell having internal resistance of $5 \Omega$,then the measured value of $R$ will be more than $1000 \Omega$.

The resistance of an ammeter is $13\, \Omega$ and its scale is graduated for a current up to $100\, A$. After an additional shunt has been connected to this ammeter,it becomes possible to measure currents up to $750\, A$ by this meter. The value of the shunt resistance is:

$A$ rectangular coil of effective area $0.05 \ m^2$ is suspended freely in a radial magnetic field of $0.01 \ Wb/m^2$. The torsional constant of the suspension fiber is $5 \times 10^{-9} \ Nm/\text{degree}$. If a current of $300 \ \mu A$ is passed through it,then the angle through which the coil rotates is (in $^{\circ}$)

When a galvanometer is shunted with a $4\,\Omega$ resistance,the deflection is reduced to one-fifth. If the galvanometer is further shunted with a $2\,\Omega$ wire,the further reduction in the deflection will be (the main current remains same).