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