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Problem: A -10.0nC point charge and a +20.0nC point charge are 15.0cm apart on the x-axis.a) What is the magnitude of the electric field at the point on the x-axis, between the charges, where the electric potential is zero? b) What is the direction of the electric field at the point on the x-axis, between the charges, where the electric potential is zero?

FREE Expert Solution

Electric field:

E=kqr2

Electric potential:

V=kqr

(a) 

The point with zero potential is located between the two charges. Let the point be x m from the -10.0nC point charge

r10 = x m

r20 = (d - x) m, where d is the separation of the two point charges.

d = 15 cm(1m/100cm) = 0.15 m

q1 = -10.0 nC (10-9C/1nC) = -10.0 × 10-9 C

q2 = 20.0 nC (10-9C/1nC) = 20.0 × 10-9 C

V1+V2=0-V1=V2-kq1r10=kq2r20--10.0×10-9x=20.0×10-90.15-x0.15-x=2x0.153=x

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Problem Details

A -10.0nC point charge and a +20.0nC point charge are 15.0cm apart on the x-axis.

a) What is the magnitude of the electric field at the point on the x-axis, between the charges, where the electric potential is zero? 

b) What is the direction of the electric field at the point on the x-axis, between the charges, where the electric potential is zero?

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