Question

Two point charges $q_1=2\mu C$ and $q_2=1\mu C$ are placed at distances $b=1cm$ and $a=2cm$ from the origin on the y and x axes as shown in figure. The electric field vector at point $(a,b)$ will subtend an angle $\theta$ with the x - axis given by :

• A. tan $\theta =1$
• B. tan $\theta =2$
• C. tan $\theta =3$
• D. tan $\theta =4$

Answer 1

The correct option is A tan $\theta =1$

$E_{eff}$ $\cos \theta =\frac{k{q}_1}{a^2}$

$E_{eff}$ $\sin \theta =\frac{k{q}_2}{b^2}$

$tan\theta =\frac{k{q}_2}{b^2}\times \frac{a^2}{k{q}_1}$

$tan\theta =\frac{(2{)}^2}{(1{)}^2}\times \frac{1\times {10}^{-6}}{2\times {10}^{-6}}$

$tan\theta =2$