An ammeter, suspected to give inaccurate reading, is connected in series with a silver voltameter. The ammeter indicates $0.54\, A$. A steady current passed for one hour deposits $2.0124\, g$ of silver. If the $E.C.E.$ of silver is $1.118 \times 10^{-3}\, g\, C^{-1}$, then the error in ammeter reading is ................ $A$.

$A$ galvanometer of resistance $50 \Omega$ is connected to a battery of $3 \text{ V}$ along with a resistance of $2950 \Omega$ in series,showing a full-scale deflection of $30$ divisions. The additional series resistance required to reduce the deflection to $20$ divisions is: (in $Omega$)

Moving coil galvanometers $M_{1}$ and $M_{2}$ have resistance,number of turns,area of coil,and magnetic field as follows:
$R_{1}=10 \Omega, R_{2}=14 \Omega, N_{1}=30, N_{2}=42$
$A_{1}=3.6 \times 10^{-3} \ m^{2}, A_{2}=1.8 \times 10^{-2} \ m^{2}, B_{1}=0.25 \ T, B_{2}=0.50 \ T$
(Spring constants are same for both galvanometers).
The ratio of $(i)$ current sensitivity and (ii) voltage sensitivity for galvanometer ($M_{2}$ to $M_{1}$) is respectively:

$A$ galvanometer having a coil resistance $100 \; \Omega$ gives a full-scale deflection when a current of $1 \; mA$ is passed through it. What is the value of the resistance in $k\Omega$ which can convert this galvanometer into a voltmeter giving full-scale deflection for a potential difference of $10 \; V$?

Which of the following does not depend upon the magnetic effect of current?

The current sensitivity of a moving coil galvanometer increases by $20 \%$ when its resistance is doubled. Calculate,by what factor does the voltage sensitivity change?