the p.d of 12v is applied to a 7.5 resistance for a period of 5seconds. calculate the electric charge transferred in this time

3 answers

12V/7.5Ω = 1.6A

and, as you know, 1A = 1 coulomb/sec

so plug and chug
12 vdc - correct?

use ohms law where voltage (EMF) = 12 volts DC and resistance = 7.5 ohms:

V = I*R or voltage = current x resistance

so current = I = 12/7.5 = 1.6 amps

now you have a steady-state circuit with 1.6 amps of current flow for 5 seconds

how many coulombs flow past a point in 5 seconds if the current flow is 1.6 amps?
A voltage of 20 V is required to cause a current of 2 A to flow in a resistor of resistance 10 Ω. What voltage would be required to make the same current flow if the resistance were 40 Ω?