2.4 Series Circuit and Parallel Circuit

8/2/2019 2.4 Series Circuit and Parallel Circuit

1/17

2.4 SeriesCircuit and

Parallel Circuit

SHAHIDMUKHLIS

FORM 5


2/17

Resistance,Current and Potential Difference in Series Circuit

EffectiveResistance:

R = R1 + R2

Current: I1 = I2 = I3

PotentialDifference

V = V1 + V2


3/17

Resistance,Current and Potential Difference in Parallel Circuit

EffectiveResistance:

R = (R1 + R2 +R

3

)-1

Current: I = I1 + I2 + I3

PotentialDifference

V = V1 = V2 = V3


4/17

What is the effectiveresistance of the connection shown in the picture below?

Answer:a. Effective resistance, R = 2 + 3 + 6 = 11b. Effective resistance, R = (1/5 + 1/5)-1 = 2.5


5/17

Find the resultantresistance of the arrangement below.


6/17

Current in Series Circuit

The current flow into a resistor = the current flow inside theresistor = the current flows out from the resistor (I1 = I2 = I3)

In a series circuit, thecurrent at any points ofthe circuit is the same.


7/17

Current in Parallel Circuit The current flow into a parallel circuit is equal to the

sum of the current in each branches of the circuit.

(I = I1 + I2)

Example:

If the resistance of the 2 resistors is the same, current will bedivided equally to both of the resistor.


8/17

In each of the diagrams below, find the reading of theammeter.

Answer:

a. In a series circuit, the current at any points ofthe circuit is the same. Therefore, the reading

of the ammeter is also 0.5A.

b. Reading of the ammeter, I = 6A - 2A = 4A


9/17

In the diagram behind ,

a.find the reading of theammeter.

a.find the current flowsthrough each of the resistors.Answer:

a.Resistance of the (whole) circuit = 2 + 4 = 6Potential difference across the whole circuit, V = 12VCurrent, I = ?V = IR(12) = I(6)

I = 2AReading of the ammeter = 2A

b.Since in a series circuit, the current at any points of the circuit is the same.Therefore, the current flows through each of the resistors is also 2A.


10/17

Potential

Difference in Series Circuit

The sum of the potential difference across individual resistor in

between 2 points in a series circuit is equal to the potential

difference across the two point.

V = V1 + V2


11/17

Potential

Difference in Parallel Circuit

The potential difference across all the resistor in a parallel circuit is the same.

V = V1 = V2


12/17

Find the reading of the given voltmeter(s) in thediagrams below

Asnwer:

a. Reading of the voltmeter, V2 = 12 - 7 = 5V

b. The potential difference across all the resistor in a parallelcircuit is the same. Therefore, the reading of the voltmeter V1is also 5V


13/17

Find the potentialacross each of the resistors in the diagram above.

Answer:

The potential difference across the wholecircuit = 12V, but the potential across the 2resistor R1 and R2 are unknown. In orderto find the potential difference across theresostors, we need to find current passingthrough the resistors.

V = 12V, R = 6, I = ?V = IR(12) = I(6)

I = 2AFor resistor R1,R = 2, I = 2A, V = ?V = IR

V = (2)(2) = 4VFor resistor R2,R = 4, I = 2A, V = ?

V = IRV = (2)(4) = 8V

The potential difference across theresistors R1 and R2 are 4V and 8Vrespectively.


14/17

Potential

Difference and E.M.F

If we assume that there is nointernal resistance in the cell,the potential differenceacross the cell is equal to thee.m.f. of the cell.


15/17

Potential

Change in a Series Circuit

V1 = V2 = V5V3 + V4 = V5


16/17

PotentialChange in a Parallel Circuit

V1 = V2 = V3 = V4


17/17

Find the reading of the voltmeter in each of the circuit below.

Reading of the volmeter = e.m.f. = 3V . Reading of the volmeter = e.m.f. = 3V

Reading of the volmeter = e.m.f. = 3V Reading of the volmeter = e.m.f. = 3V

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2.4 Series Circuit and Parallel Circuit