Question

An electric bulb of resistance 20 Ω and a resistance wire of 4 Ω are connected in series with a 6 V battery.
Draw the circuit diagram, and calculate:

(a) total resistance of the circuit.
(b) current through the circuit.
(c) potential difference across the electric bulb.
(d) potential difference across the resistance wire.

Answer 1

 

(a) Total resistance, R = 20 Ω + 4 Ω = 24 Ω
(b) Current through the circuit,
     I = V/R 
     I = 6/24
     I = 0.25 A
(c) Potential difference across the electric bulb,
 V_bulb = IR_bulb
          `=0.25xx20`
          = 5 V
(d) Potential difference across the resistance wire,
V_wire = IR_wire
         `= 0.25xx4`
         =  1 V