Electric power and emf

In summary, a battery supplies a steady current of 5.6 A for 21 s, transforming 1410 J of chemical energy into electric energy. However, 560 J of this electric energy is transformed into heat energy inside the battery. The total power output of the battery is the sum of these two energies, which is equal to 850 J. Therefore, the total power output of the battery is 850 J.
  • #1
daysrunaway
19
0

Homework Statement


A battery supplies a steady current of 5.6 A for 21 s. During this time 1410 J of chemical energy is transformed into electric energy, but 560 J of this electric energy is transformed into heat energy inside the battery. What is the total power output of the battery?


Homework Equations


P = E/t


The Attempt at a Solution


What is confusing me is: is the energy I should consider in the "total power output" the energy associated with the emf - 1410 J - or the energy associated with the terminal voltage - 1410 J – 560 J = 850 J? I don't understand why I should use one or the other.

The next question asks pretty much the same question but with emf and current, and doesn't even give a terminal voltage, so I am guessing I should use 1410 J, but I don't understand why this is. Could someone please help explain?
 
Physics news on Phys.org
  • #2
The way I read it, the battery puts out two kinds of power, thermal, that heats its surroundings, and electrical that does what it does in the circuit. Total power would be the sum of the two.
 

What is electric power and how is it measured?

Electric power is the rate at which electrical energy is transferred or consumed. It is measured in watts (W) and can be calculated by multiplying the voltage (V) by the current (I). This calculation can also be represented as P = VI.

What is electromagnetic force (emf) and how is it related to electric power?

Electromagnetic force (emf) is the potential difference that exists between two points in a circuit. It is measured in volts (V) and is responsible for the flow of electric current. Electric power is related to emf because the rate at which electric power is transferred is dependent on the emf in a circuit.

What are the different types of electric power sources?

There are three main types of electric power sources: batteries, generators, and solar panels. Batteries store chemical energy and convert it into electrical energy. Generators convert mechanical energy into electrical energy. Solar panels use the sun's energy to generate electricity through the photovoltaic effect.

How does alternating current (AC) differ from direct current (DC)?

Alternating current (AC) is a type of electric current that periodically reverses direction, while direct current (DC) flows in only one direction. AC is commonly used in household outlets and power grids, while DC is typically used in batteries and electronic devices.

What are some common applications of electric power and emf in everyday life?

Electric power and emf have a wide range of applications in everyday life, including powering household appliances, charging electronic devices, and providing lighting in homes and businesses. They are also used in transportation, such as powering electric cars and trains. Additionally, emf plays a crucial role in medical equipment, such as MRI machines, and in industrial processes, such as welding and electroplating.

Similar threads

  • Introductory Physics Homework Help
Replies
4
Views
182
Replies
11
Views
616
  • Introductory Physics Homework Help
Replies
19
Views
1K
  • Introductory Physics Homework Help
Replies
22
Views
1K
  • Introductory Physics Homework Help
Replies
1
Views
711
  • Introductory Physics Homework Help
Replies
5
Views
946
  • Introductory Physics Homework Help
Replies
7
Views
898
  • Introductory Physics Homework Help
Replies
6
Views
1K
Replies
4
Views
746
  • Introductory Physics Homework Help
Replies
7
Views
1K
Back
Top