Answer:
The number of bulbs = 46 bulbs
Explanation:
Ohm's Law: Ohm's law states that the current flowing through a conductor is directly proportional to its potential difference across its ends. At constant temperature and pressure. It can be expressed mathematically as
V = IR............. Equation 1
making R the subject of formula in equation 1
R = V/I.............. Equation 2
Where R = combined resistance of the several bulbs, V = potential difference, I = current through the circuit.
Given: V= 115 V. I = 2 A.
Substituting these values into equation 2,
R = 115/2
R = 57.5 Ω
Since the bulbs are connected in series,
Number of bulbs = combined resistance/resistance of each bulb
Number of bulbs = R/Rₙ...................... Equation 3
Where Rₙ = resistance of each bulb, R =combined resistance of the bulb.
Also given: Rₙ = 1.25 Ω, and R = 57.5 Ω
Substituting these values into equation 3
Number of bulbs = 57.5/1.25
Number of bulbs = 46 bulbs.
Therefore the number of bulbs = 46 bulbs
