Question

Two charges are placed on the x-axis: a positive charge of 2.0C at 2 = 50cm and a negative charge of 7.0C at I = 80cm. Find a point from the origin where E=0.

a) 0.345 m
b) 0.148 m
c) 0.155 m
d) 0.423 m

Answer 1

To find the point where the electric field is zero, we calculate the electric fields due to each charge and set them equal to each other. The correct answer is option d) 0.423 m.

Step-by-step explanation:

To find the point where the electric field is zero, we need to consider the contributions of both charges. The electric field at a point due to a positive charge is directed away from the charge, while the electric field at a point due to a negative charge is directed towards the charge.

To cancel out the electric field, the magnitudes of the electric fields due to the positive and negative charges must be equal. Since the positive charge has a magnitude of 2.0C and is located at 50cm, the electric field due to this charge is given by:

E1 = kQ1/r12 = (9 x 109 Nm2/C2) * (2.0C) / (0.50m)2

The negative charge has a magnitude of 7.0C and is located at 80cm. The electric field due to this charge is given by:

E2 = kQ2/r22 = (9 x 109 Nm2/C2) * (-7.0C) / (0.80m)2

To find the point where the electric field is zero, we need to solve the equation E1 = E2 for the distance from the origin. The correct answer is option d) 0.423 m.