The magnetic moment \( \vec{M} \) is given by:
\[ \vec{M} = I \vec{A}. \]With \( I = 5 \, \text{A} \), \( A = 0.2 \times 0.1 = 0.02 \, \text{m}^2 \), and \( \vec{A} = 0.02 \, \hat{i} \), we get:
\[ \vec{M} = 5 \times 0.02 \, \hat{i} = 0.1 \, \hat{i}. \]The torque \( \vec{\tau} \) is given by:
\[ \vec{\tau} = \vec{M} \times \vec{B}. \]Substituting \( \vec{B} = 2 \times 10^{-3} \, \hat{j} \):
\[ \vec{\tau} = 0.1 \, \hat{i} \times 2 \times 10^{-3} \, \hat{j} = 2 \times 10^{-4} \, (-\hat{k}) = 2 \times 10^{-4} \, \text{Nm}. \]Therefore, the answer is:
\[ 2 \times 10^{-4} \, \text{Nm} \text{ along the negative Z-direction.} \]The number of turns of the coil of a moving coil galvanometer is increased in order to increase current sensitivity by $50 \%$ The percentage change in voltage sensitivity of the galvanometer will be: