Duas partículas eletrizadas com cargas iguais a +25uC estão colocadas a 1,0m uma da outra, no vácuo, onde a constante eletrostática vale 9.10^9 unidades do Sistema Internacional. Não havendo influência de outras cargas, determine: a) a intensidade do campo eletrostático que cada carga cria no ponto P, situado a meia distancia entre elas;

b) a forca resultante que age numa carga de prova de +2,0uC colocada em P.

The heater element of a 120 v toaster is a 5.4 m length of nichrome wire, whose diameter is 0.48 mm. the resistivity of nichrome at the operating temperature of the toaster is 1.3 × 10-6 ω·m. the toaster is operated at a voltage of 120 v. (a) what is the power drawn by the toaster? (b) if the cost of electricity is 12 ¢ per kilowatt-hour, and it takes 2 minutes to toast bread, how much does it cost for toasted bread? (c) when the heater element is at room temperature, is the resistivity in the nichrome wire greater than, less than, or equal to it’s resistivity when at operating temperature? explain.