A charge Q is placed

1. at the centre of the cube

2.at the centre of face

3.at the centre of edge

4.at one of its corner

find total electric flux through

a)The surfaces of cube

b)individual surfaces

gauss' law cant be implemented as charge lies on the surface

any other method i dont seem fruitful

rate me!!

q/epsilon knot for all the surfaces and q/6epsilon for individual surfaces

hey man its easy

center of cube q/epsilon0

center of edge  q/4epsilon0

at one corner  q/8epsilon0

hope i m right or i need a revision........

please explain

center of the edge=q/4epsilon 0

which gaussian surfaces r u using for determining the result????

dont u remember that for determing E.F. thru a closed surface , no charge must lie on the gaussian surface

whats ur opinion

@rahulraj

SEE, U WANT AN EXPLANATION FOR CHARGE KEPT AT CENTRE OF THE EDGE. NOW IF THE CHARGE IS KEPT AT THE CENTRE OF THE EDGE , ONLY Q/4 CHARGE WILL BE INSIDE THT CHARGE BECAUSE TO COMPLETELY COVER THT CHARGE V WILL REQUIRE FOUR SUCH CUBES.HENCE THE FLUX THROUGH ALL THE FACES WILL BE

 

THIS IS THE TOTAL FLUX PASSING THROUGH ALL THE FACES. NOW SINCE THE CHARGE IS IN CONTACT WITH TWO FACES , NO FLUX WILL PASS THROUGH THEM, HENCE THIS TOTAL FLUX WILL PASS THROUGH REMAINING FOUR FACES.

HENCE FLUX THROUGH EACH FACE WILL BE

hope u can understand the solution now

RATE IF SATISFIED OR U CAN ASK FURTHER.   

for charges at surface u can do like this assume two cubes and charge 2q at their common face. find total flux through both cube treating them as one object by gauss law and then divide the answer by 2 to get the flux by one cube(by symmetry).







similalry u can do for charge at the edge. at edge keep 8q charge coz a corner shared by 8 cube.

gauss law can be easily apllied ...its impossible for human to solve this ques otherwise...for charges on edges and surface put four cubes and two cubes resp...just like we did it in solid state...charges on edges are shared by four equivalent cubes and on faces by two equivalent cubes...so gauss law and those structure in solid state are somewhat related...and similarly for corner wch is shared by 8 cubes and for centre its 1...rest can be done urslf...idea is this.....