Question $2$:

$(25$ marks$)$

The circular disc of radius $\text{'}a\text{'}$ shown in Figure Q$-2,$ has uniform charge density ${}_s$ across its surface.

a$)$ Obtain an expression for the electric potential $V$ at appoint $P(0,0,h)$ on the z $-$axis.

b$)$ Use your result to find $E$ and then evaluate it for $z=h.$

Figure $0-2$