What is a gaussian surface?

What must be the shape of a gaussian surface?

Five charges q_1, q_2, q_3,q_4 and q_5 are fixed at their positions as shown in Fig. S is a Gaussian surface. The Gauss's law is given by int E.dS = q/epsilon Which of the following statements is correct?

What is the importance of gaussian surface?

What is the use of Gaussian surface in electrostatics ?

A spherical gaussian surface encloses a charge of 8.85 xx 10^-8C If the radius of the gaussian surface is doubled, hwo would the flux change?

Refer to the arrangement of charges in Fig. and a gaussian surface of radius R with Q at the centre.Then,