1.
[tex]Dane:\\q = 90 \ C\\t = 6 \ min = 6\cdot 60 \ s =360 \ s\\Szukane:\\I = ?\\\\\\I = \frac{q}{t}\\\\I = \frac{90 \ C}{360 \ s}\\\\\boxed{I = 0,25 \ A}[/tex]
2.
[tex]Dane:\\t = 4 \ min = 4\cdot60 \ s = 240 \ s\\I = 50 \ mA = 0,05 \ A\\Szukane:\\q = ?\\\\\\I = \frac{q}{t} \ \ /\cdot t\\\\q = I\cdot t\\\\q = 0,05 \ A\cdot240 \ s\\\\\boxed{q = 12 \ C}[/tex]
3.
[tex]Dane:\\q = 70 \ C\\I = 3,5 \ A\\Szukane:\\t = ?\\\\\\I = \frac{q}{t} \ \ /\cdot t\\\\I\cdot t = q \ \ /:I\\\\t = \frac{q}{I}\\\\t = \frac{70 \ C}{3,5 \ A}\\\\\boxed{t = 20 \ s}[/tex]
4.
[tex]1 \ kV = 1000 \ V\\1 \ mV = 0,001 \ V\\\\\\a) \ 1,6 \ kV = 1,6\cdot1000 \ V = 1 \ 600 \ V\\\\b) \ 125 \ mV = 125\cdot0,001 \ V = 0,125 \ V[/tex]