Two points charge q (√10 C) and q2 (-25C) are placed on the axis at x=1 and x=4cm, respectively. The electric field (in V/m) at a point you=3cm on Y axis is

 Two points charge q (√10 C) and q2 (-25C) are placed on the axis at x=1 and x=4cm, respectively. The electric field (in V/m) at a point you=3cm on Y axis is 

Pg-386 q. 73

Ans. 

Let us given 

q1=√10 C

q2=(-25 C) , here sign represent direction

Here we have to find Enet

i.e E1+E2.

E1 (Electric field) will be at x=1cm.

E1=kq1/r^2

  =9*10^9 *√10*10^-6/(√1^2+3^2) ^2

 =9*10^3/√10

 

In vector form, 

E1=9*10^3/√10(costheta i- sinetheta j) 

E1=9*10^3/√10*(1/√10 i- 3/√10 j) 

E1=[-9i+27j]*10^2 V/m

Similarly, 

E2, at x=4

E2=(72i-54j) *10^2 V/m

Now, 

Enet=E1+E2

        =(63i-27j) *10^2 V/m