# Electrics (last minute check up for test tommorrow)

• stardust rain
In summary, The conversation is about electricity and its various components such as current, resistance, voltage, and energy transfer. The speaker is struggling to understand the relationship between energy transfer and power, and is seeking help and advice on the subject. The formula for power is mentioned as P = dW/dt, where W is the work and P is the power. Overall, the speaker is seeking clarification and assistance with their understanding of electricity.
stardust rain
Electrics -Power, energy transfer- (last minute check up for test tommorrow)

(Long time lurker, first time poster here. Hi all)

I've learned about current, coloumb (sp?) resistance, voltage and so on. I know that resistance is V/I, how to caltulate colombs but I get really confused when it comes to energy transfer and power.

I know the formula, but I don't understand it at all. Can you work out the power from just the energy output and time taken? What does it mean by energy transfer? Can you work that out from the current, time and power?

And also, I'd like any other help/advice concernig electricity as well.

*Any* help would really, really appreciated, since this text is going to decide on my grade for the term. And I'm on fail level right now thanks to a crappy teacher.

Last edited:
I guess if W is the work then that is the Energy,
and Power is really is synonym for dW/dt = P the power.

So that is that.

By the way W = Integral_over_time[Power] !

Hi there, it sounds like you have a good understanding of the basic concepts of electricity. Power and energy transfer can be a bit tricky to understand at first, but let's break it down.

Power is the rate at which energy is transferred or converted. It is measured in watts (W) and is calculated by dividing the energy transferred (in joules) by the time it takes (in seconds). So, if you know the energy output and time taken, you can definitely work out the power.

Energy transfer, on the other hand, refers to the movement of energy from one place to another. In the context of electricity, it refers to the flow of electrical energy from a power source to a device. This can also be calculated using the formula for power, as energy transfer is essentially the same as power.

In terms of other advice for your test tomorrow, I would recommend reviewing any notes or practice problems you have done in class. Also, try to understand the concepts rather than just memorizing formulas. If you have any specific questions or areas you are struggling with, don't hesitate to ask your teacher or classmates for help.

Good luck on your test tomorrow! I'm sure with some last minute review and understanding of the concepts, you will do great. Don't let one bad teacher bring you down, keep pushing and learning. You got this!

## 1. What is the difference between AC and DC electricity?

AC (alternating current) electricity changes direction periodically, while DC (direct current) electricity flows in one direction consistently. AC is used for long-distance power transmission, while DC is typically used for electronic devices.

## 2. What is the unit of measurement for electrical current?

The unit of measurement for electrical current is the ampere (A).

## 3. How is electrical resistance calculated?

Electrical resistance is calculated using Ohm's Law: R = V/I, where R is resistance in ohms (Ω), V is voltage in volts (V), and I is current in amperes (A).

## 4. What is the purpose of a circuit breaker?

A circuit breaker is designed to automatically interrupt the flow of electricity in a circuit when it detects an overload or short circuit, preventing damage to the circuit and potential hazards.

## 5. Can electricity be generated from renewable sources?

Yes, electricity can be generated from renewable sources such as solar, wind, hydro, and geothermal power. These sources do not deplete natural resources and have a lower impact on the environment compared to traditional fossil fuels.

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