[填空题]
How much energy is stored by the y*eqh nk x;ac*hx4g .4electric fieldfr duka ,fp 4 */fkotrw+t)8l4 between two square plates, 8.0 cm on a side, separated by a 1.5-mm air gap? The charges on thlfp)f4rkr4 td*8+at,o/ w ukf e plates are equal and opposite and of magnitude $420\mu C$. J
