Two charges , q1=+2.0 x 10-6C, and q2= +4.0 x 10-6C, are placed in a vacuum, 20cm apart. At what point on the line joining the two charges is the electric field strength equal to zero?

1 Answer
Apr 28, 2017

#x=8.3 cm#
#"The Point O(8.3,0)"#

Explanation:

enter image source here

#"Since The Electrical fields vectors of the charges Q1 and Q2"#
#"is at opposite direction,The point that we are looking for "#
#"should be in the white area."#
#"The vectors at the green and blue areas have the same direction."# #"The sum of these vectors not be zero."#

#cancel(K)*Q_1/x^2=cancel(K)*Q_2/(0.2-x)^2#

#(cancel(2)*cancel(10^(-6)))/x^2=(cancel(4)*cancel(10^(-6)))/(0.2-x)^2#

#1/x^2=2/(0.2-x)^2#

#sqrt(1/x^2)=sqrt(2/(0.2-x)^2)#

#1/x=(1.41)/(0.2-x)#

#1.41x=0.2-x#

#2.41x=0.2#

#x=(0.2)/(2.41)#

#x=0.083 " "m#

#x=8.3 cm#