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

$A$ galvanometer of resistance $G$ is converted into a voltmeter of range $0-1\, V$ by connecting a resistance $R_{1}$ in series with it. The additional resistance that should be connected in series with $R_{1}$ to increase the range of the voltmeter to $0-2\, V$ will be

In a moving coil galvanometer,two moving coils $M_1$ and $M_2$ have the following particulars:
$R_1 = 5 \ \Omega, N_1 = 15, A_1 = 3.6 \times 10^{-3} \ m^2, B_1 = 0.25 \ T$
$R_2 = 7 \ \Omega, N_2 = 21, A_2 = 1.8 \times 10^{-3} \ m^2, B_2 = 0.50 \ T$
Assuming that the torsional constant of the springs is the same for both coils,what will be the ratio of the voltage sensitivity of $M_1$ and $M_2$?

Two moving coil meters,$M_{1}$ and $M_{2}$ have the following particulars:
$R_{1}=10 \,\Omega, \quad N_{1}=30$
$A_{1}=3.6 \times 10^{-3} \,m^{2}, \quad B_{1}=0.25 \,T$
$R_{2}=14 \,\Omega, \quad N_{2}=42$
$A_{2}=1.8 \times 10^{-3} \,m^{2}, \quad B_{2}=0.50 \,T$
(The spring constants are identical for the two meters). Determine the ratio of
$(a)$ current sensitivity and
$(b)$ voltage sensitivity of $M_{2}$ and $M_{1}$.

Derive the expression for the shunt resistance required to increase the current-measuring capacity of a galvanometer by a factor of $n$.

The range of an ammeter of resistance $G$ can be increased from $I$ to $nI$ by connecting