The figure shows a new circuit. [Page 589]
When the circuit is switched on the ammeter reads 0.5 A.
i) Calculate the value of the unknown resistor R.
ii) Calculate the charge passing through the 3 ohm resistor in 120 s
iii) Calculate the power dissipated in the 3 ohm resistor.i)
ii)
iii)
Power, P = V.I.
= I2R
= (0.5)2 x 3
= 0.25 x 3
P = 0.75 Watt
Two resistors of 4 ohm and 6 ohm are connected in parallel to a cell to draw 0.5 A current from the cell.
i) Draw a labeled circuit diagram showing the above arrangement.
ii) Calculate the current in each resistor.i) The labeled circuit diagram is shown as below:
ii) 
Three resistors are connected to a 6 V battery as shown in the figure given below: 
Calculate:
i) the equivalent resistance of the circuit.
ii) total current in the circuit.
iii) potential difference across the 7.2 ohm resistor
Reistors 8 ohm and 12 ohm are in parallel.
Then, equivalent resistance is, 
Three resistors are connected to a 12 V battery as shown in the figure given below:
i) What is the current through the 8 ohm resistor?
ii) What is the potential difference across the parallel combination of 6 ohm and 12 ohm resistor?
iii) What is the current through the 6 ohm resistor?
Here, 12 ohm and 6 ohm resistors are connected in parallel.
Therefore, their effective resistance, 
Total resistance of the circuit = 8+4 = 12
i) Current drawn = 
That is, current through the 8 om resistor = 1 A
ii) P.D. across the 8 ohm resistor = I R = 1 = 8 V
P.D. across the parallel combination of resistors = 12 – 8 = 4 V
Because, the resistances are in parallel and they have the same P.D. each.
That is equal to 4 V.
iii) Current through the 6 ohm resistor =
Five resistors of different resistances connected together as shown in the figure. A 12 V battery is connected in the arrangement. 
Calculate:
i) the total resistance in the circuit.
ii) the total current flowing in the circuit.Here R1 and R2 are connected in parallel. 
And R3, R4 and R5 are in parallel.
That is, 
i)Total resistance = R + R’ = 8 +10 = 18 ohm
ii) Total current = =0.67 A
Switch
