Дано:q=17,7нКл=17,7*10^-9Кл
<span>S=10см^2=0,001м^2
</span><span>d=3,5мм=0,0035м
</span><span><em>ε</em>=8
</span>W-?
<span>W=q^2/2C, C=<em> ε ε</em>oS/d, C=8*8,85*10^-12*0,001/0,0035=20,22*10^-12Ф
</span><span>W=17,7*10^-9*17,7*10^-9/40,44*10^-12=7,7*10^-6Дж=7,7мкДж</span>