Power consumption Definition and 55 Threads

This isn't exactly a physics question, more of a household debate/puzzle: You get a laptop and it comes from the factory with the battery fully charged. It takes 1 hour of being plugged in (with the computer on and in use) to charge, and gives 3 hours of use (when unplugged, of course). Let's...

Homework Statement A motor attached to a 120 V/60 Hz power line draws an 7.60 A current. Its average energy dissipation is 840 W. How much series capacitance needs to be added to increase the power factor to 1.0? (in micro F) Homework Equations Don't know which to use at all. The...

Is it possible to check somewhere (BIOS, etc) the total amount of power used by the computer? I have a 430W PSU and I want to add another fan, and I'm not sure I want to risk overloading it.

to measure the amount of power drawn by an appliance, can we simply multiply the voltage (V) of the mains by the current (I)drawn (measured using a digital clamp meter) by the appliance to obtain power (P=I x V). does the power company charge us (rate x Power) based of this value P, regardless...

I heard that a dimmer switch/knob/potentiometer used to control the lights in a house, for example, uses the same amount of power no matter if it is just barely on, or turned up all the way, so it really doesn't matter (energy usage wise), what the switch is turned to, it will use the same...