Question

A wire of mass 100g is carrying a current of 2A in the form of $y\, =\, x^2 (-􏰅2 ≤ x ≤ 2)$. The wire is place 􏰆y in a magnetic field $\vec{B}$ = $-0.02 \hat{k} \,T$ The acceleration of wire in $(m/s^2)$ is (Neglect gravity and x and y are in metre)

• A. $−1.6 \hat {j}$
• B. $−3.2 \hat {j}$
• C. $−1.6 \hat {j}$
• D. Zero

Answer 1

Answer: (C)

$\vec{F} =2\left[4\hat{i}\times\left(-0.02\hat{k}\right)\right]=0.16\hat{j}$
$\vec{F} = i\left(\vec{I}\times\vec{B}\right)$
$\vec{F} =2\left[4\hat{i}\times\left(-0.02\hat{k}\right)\right]=0.16\hat{j}$
$\overrightarrow{a} =\frac{\vec{F}}{m} = \frac{0.16 \hat{j}}{100\times10^{-3}}=1.6\hat{j}\, m/s^2 $