Question

Two charges $+3.2\times {10}^{-19}\text{C}\text{and}-3.2\times {10}^{19}\text{C}$ placed $2.4{\text{A}}^{\circ }$ apart form an electric dipole. It is placed in a uniform electric field of intensity $4\times {10}^5\text{V/m}$, the workdone to rotate the electric dipole from the equilibrium position by ${180}^{\circ }$ is $\times {10}^{-23}J$

• A. 6.14
• B. 6.1
• C. 6

Answer 1

Answer: (A), (B), (C)

$q=3.2\times {10}^{-19}\text{C};d=2a=2.4\times {10}^{-10}\text{m}$

$E=4\times {10}^5\text{V/m}$.

Workdone in rotating a dipole , $W=pE[1-\cos \theta ]$

$=q\left(2a\right)E[1-\cos {180}^{\circ }]$

$=3.2\times {10}^{-19}\times 2.4\times {10}^{-10}\times 4\times {10}^5\times \left[2\right]$

$=61.44\times {10}^{-24}\text{J}\text{or}6.14\times {10}^{-23}\text{J}$