Question

A uniform electric field exists in $x-y$ plane. The potential of points $A(-2\, m ,\, 2\, m ), \,B(-2\, m ,\, 2\, m )$ and $C(2\, m ,\, 4\, m )$ are $4\, V ,\, 16\, V$ and $12\, V$, respectively. The electric field is

• A. $(4 \hat{i}+5 \hat{j}) \frac{ V }{ m }$
• B. $(3 \hat{i}+4 \hat{j}) \frac{ V }{ m }$
• C. $-(3 \hat{i}+4 \hat{j}) \frac{ V }{ m }$
• D. $(3 \hat{i}-4 \hat{j}) \frac{ V }{ m }$

Answer 1

Answer: (D)

$\vec{E}_{x}=\frac{16-4}{2} \hat{i}=3 \hat{i}$
$\vec{E}_{y}= -\frac{12-4}{2} \hat{j}= -4 \hat{j}$
$\vec{E}=(3 \hat{i}-4 \hat{j}) Vm ^{-1}$