Question

There is an electric field $E$ in $ x- $ direction. If the work done on moving a charge $0.2\, C$ through a distance of $2\, m$ along a line making an angle $ 60{}^\circ $ with the $ x- $ axis is $4.0$, what is the value of $E$ ?

• A. $ \sqrt{3} $ N/C
• B. 4 N/C
• C. 5 N/C
• D. None of these

Answer 1

Answer: (D)

$ W=qV=q\overrightarrow{E}.\overrightarrow{d} $
$ 4=0.2\times E\times (2\text{ }cos\text{ }60{}^\circ ) $
$ 4=0.2\times E\times 2\times 0.5 $
$ E=\frac{4}{0.2}=20\,N/C $