Electrical= Resistance and Energy

In summary, A wire with a resistance of 9.0 is connected to a battery with an emf of 3.0 V and an internal resistance of 1.0. In 4.0 minutes, 216 joules of energy is transferred from chemical to electrical form. However, the energy appearing in the wire as thermal energy is not 189.629 joules as previously calculated, but rather 194.4 joules due to the high resistance of the battery being a significant component in the overall resistance of the circuit.
  • #1
Forceflow
30
0
A wire of resistance 9.0 is connected to a battery whose emf is 3.0 V and whose internal resistance is 1.0 .
(a) How much energy is transferred from chemical to electrical form in 4.0 min?
(b) How much energy appears in the wire as thermal energy in that time?

answer to a= 216 (that's correct)
for b, i got 189.629 (that one is wrong though)

For the work, i did: I= 3V/9 = .3333 A
Vtotal= 3V-IR
Vtotal= 3V-.333(1)
Vtotal= 2.6666
p=Vsquared/R
P=2.666 squared/9
P= .79011
.79011 (4) (60) = 189.62
 
Physics news on Phys.org
  • #2
When calculating the current -- why would you ignore the resistance of the battery? (Normally you would, but in this case it is a fairly high component of the overall resistance of the circuit)
 
  • #3
i would ignore it because its asking for the energy in the wire specifically..i believe anyway
 
  • #4
if for a new answer, i got 194.4 joules..would that be correct?
 
  • #5
is 194.4 the answer?
 

1. What is electrical resistance?

Electrical resistance is the measure of how difficult it is for electricity to flow through a material. It is caused by collisions between electrons and atoms in the material.

2. How is electrical resistance measured?

Electrical resistance is measured in ohms (Ω) using a device called an ohmmeter. It can also be calculated by dividing the voltage (V) by the current (I) in a circuit, according to Ohm's Law: R = V/I.

3. How does temperature affect electrical resistance?

In most materials, an increase in temperature causes an increase in electrical resistance. This is because higher temperatures cause atoms to vibrate more, making it more difficult for electrons to pass through the material.

4. What are some factors that affect electrical resistance?

The three main factors that affect electrical resistance are the material of the conductor, the cross-sectional area of the conductor, and the length of the conductor. Other factors include temperature, impurities in the material, and the type of current (AC or DC).

5. How is electrical resistance related to energy?

Electrical resistance is related to energy through the Joule's Law, which states that the energy dissipated (in the form of heat) in a circuit is equal to the product of the resistance, current, and time: E = I * R * t. This means that higher resistance leads to more energy being converted to heat in a circuit.

Similar threads

Electric Potential across charging battery.
    • Introductory Physics Homework Help
Replies
5
Views
994
Electric potential at a point due to two charges
    • Introductory Physics Homework Help
Replies
2
Views
3K
RC Circuit - Rate energy is dissipated in the resistor
    • Introductory Physics Homework Help
Replies
4
Views
2K
Electrical Energy Dissipation Across Resistors
    • Introductory Physics Homework Help
Replies
5
Views
12K
Question about electrical power compared to mechanical power
    • General Engineering
Replies
8
Views
2K
High resistance or low resistance for induction cooktops?
    • Introductory Physics Homework Help
Replies
1
Views
2K
Electric Potential Difference during thunder storm
    • Introductory Physics Homework Help
Replies
12
Views
4K
The Rate at which kinetic energy changes to thermal energy
    • Introductory Physics Homework Help
Replies
2
Views
2K
Two battery hooked up in series, energy conversion
    • Introductory Physics Homework Help
Replies
4
Views
1K
The rate at which the energy in the wire is transformed into kinetic
    • Introductory Physics Homework Help
Replies
4
Views
2K

Hot Threads

Recent Insights

Back
Top