Final answer:
The value of Emax (in V/m) for the given lightbulb scenario is approximately 6.6 * 10^(-4) V/m.
Step-by-step explanation:
To find the value of Emax (in V/m) for the given lightbulb scenario, we need to substitute the given values into the formula for electric field intensity (E). The formula is E = sqrt((2 * power * efficiency) / (c * distance)), where power is the visible light output of the lightbulb, efficiency is the efficiency of the lightbulb, c is the speed of light, and distance is the distance between the lightbulb and the page.
Substituting the given values:
E = sqrt((2 * 4.2 * 0.07) / (3 * 10^8 * 0.39))
E = sqrt(0.00432 * 10^(-6))
E = 6.6 * 10^(-4) V/m
Therefore, the value of Emax (in V/m) for the given lightbulb scenario is approximately 6.6 * 10^(-4) V/m.