Q = 2V$$U_i=\\cfrac{1}{2}×\\cfrac{(2V)^2}{2}=V^2$$ $$\ herefore V_y=\\cfrac{1}{2}\\cfrac{64V^2}{25×8}$$ $$\\cfrac{2V-q}{2}=\\cfrac{q}{8}+\\cfrac{1}{2}\\cfrac{4V^2}{25×2}$$ $$\ herefore 8V-4q=q$$ $$U_r=\\cfrac{5V^2}{25}=\\cfrac{V^2}{5}$$ $$\ herefore q=\\cfrac{V^2}{5}$$ Energy dissipated $$=\\cfrac{4V^2}{5}$$ ∴ % energyDissipated $$=\\cfrac{4V^2}{5V^2}×100$$ = 80%