Final answer:
The screen consumes the most power on most mobile devices, especially when at high brightness. It acts similar to an array of resistors, dissipating power. Power consumption increases significantly when a laptop screen is turned on, drawing more current and thereby increasing the power used, calculated as 8.0 W using the formula P = IV.
Step-by-step explanation:
The component that uses the greatest amount of power on most mobile devices is the screen. Particularly, when the screen is set to high brightness levels, it consumes more power than other components. This is because the display technology, whether it is LCD, OLED, or any other type, requires lighting, which significantly increases the power draw. When we compare the power consumption of different elements in a circuit such as those in a mobile device, we observe that resistors are the ones that dissipate power. Therefore, a display with its illuminated pixels acts as a large array of resistors, each dissipating power as it lights up.
To measure the power consumed by a device like a laptop computer, an ammeter can be placed in series with its DC power supply. If the computer draws 0.40 A with the screen off, and 0.90 A with the screen on at full brightness with a power supply of 16 V, the power used by the screen can be calculated using the formula P = IV. Substituting the given values: P = (0.90 A - 0.40 A) * 16 V, yields a result of 8.0 W. Therefore, the power used by the screen is 8.0 W.