let us take ring of width (dx) at a distance x from base of cylinderdE rarr field at the top due to this{:[dE=((L-x)dq)/(4piepsilon_(0)[R^(2)+(L-x)^(2)]^(3//2))],[" \& "dq=2pi Rdx*eta],[=>dE=((L-x)2pi Rdx*eta)/(4piepsilon_(0)[R^(2)+(L-x)^(2)]^(3//2))]:}Integrating above eqn to getE=int dE=int_(0)^(L)(2pi R*eta)/(4piepsilon_(0))*((L-x)dx)/([R^(2)+(L-x)^( ... See the full answer