Final answer:
To calculate the power consumed by an iPhone charger, multiply the current (0.9A) by the voltage (120V) to get the power in watts, then multiply by the time in hours to get the energy in watt-hours. The energy consumed in 2 hours is 216Wh or 777,600 Joules.
Step-by-step explanation:
The question asks about the amount of power consumed by an iPhone charger over a period of time. To calculate the energy used, we need to know the charger's current and voltage. The current is given as 900mA (or 0.9A). However, the standard voltage for a wall socket in most regions is around 120V or 230V (depending on the country). We will use 120V for this calculation.
The power (P) can be calculated using the formula P = IV, where I is the current and V is the voltage. Thus, the power consumed is P = 0.9A * 120V = 108W. To find the energy consumed in 2 hours, we use the formula E = P * t, where E is the energy in watt-hours (Wh) and t is the time in hours. So, the energy consumed is E = 108W * 2h = 216Wh, which is the same as 216 Watt-hours or 777,600 Joules (since 1 Wh = 3600 J).