Physics Exercises/Circuits

ELECTRIC CIRCUIT SIMPLE CIRCUIT -In a simple circuit a source of EMF mantains a potential energy difference across end of the circuit -Current is the flow of charge CELLS IN SERIES -The connection of the positive pole of one cell is connected to the negative pole of the next cell -The total EMF is the sum of the individual EMF'S E.g. EMF= 1,5+1,5+1,5 =4,5 OR TEMF=1,5×3 =4,5 CELLS IN PARALLEL -All the positive poles are connected to one point and all the negative poles are connected to the other point -The EMF is the same as the EMF of a single cell E.g. EMF=1,5 ELECTRIC CURRENT -The flow of charged particles -Charge flows through conductors but it cannot pass through insulators FORMULA: I = Q ÷ ∆T Q = The charge I = Current ∆T = Time E.g.1. Calculate the current that passes through a circuit when 54C of charge flow through a light bulb for one minute SOLUTION: I = Q ÷ ∆T = 54C ÷ 60s I = 0,9A E.g.2. How much charge passes through a conductor when a current of 3A is maintained for 3 minutes SOLUTION: I = Q ÷ ∆T 3 = Q ÷ 180s = 3 ÷ 180s = 540C E.g.3. Calculate the current that passes through a circuit when 28C of charge flow through a light bulb for 5 minutes SOLUTION: I = Q ÷ ∆T = 28 ÷ 300 I = 0,093A