The cube in the figure below contains no net charge in which

The cube in the figure below contains no net charge, in which E1 = 8 N/C and E2 = 29 N/C. The electric field is constant over each face of the cube. Does the missing electric field vector on the front face point in or out? I have figured out that the electric field points out. I can\'t figure out the field strength.

What is the field strength? in N/C

Solution

Since no charge is contained, so net Flux coming out should be zero

(E1-E2+15-15+15+x)S = 0

Where S = area of one face of cube

cube

x = missing field strength

(8-29+15-15+15+x)=0

X=6

so electric field points out outwards with strength 6N/C