Answer:54 sec
Explanation:
Let's denote the number of minutes the light bulb was on by "t".
According to the problem, the light bulb uses 5.4 watts each minute it is on. Therefore, the total amount of energy consumed by the light bulb in "t" minutes is:
Energy = Power x Time = 5.4t watts
We also know that the light bulb uses a total of 4.86 watts of electric power. So we can set up an equation:
5.4t = 4.86
Solving for "t", we get:
t = 4.86 / 5.4
t ≈ 0.9
Therefore, the light bulb was on for approximately 0.9 minutes, or about 54 seconds.