Electric potential across a simple circuit

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SUMMARY

The discussion centers on calculating electric potential in a simple circuit involving a battery, switch, and resistor. The initial electric potential is denoted as V_o. Key conclusions include that when the switch is open, the electric potential before and after the battery, switch, and resistor remains at 0 volts due to no current flow. Immediately after closing the switch, the potential before the resistor equals V_o, while the potential difference across the resistor is -V_o. After a long time with the switch closed, the electric potential remains unchanged, confirming the initial findings.

PREREQUISITES
  • Understanding of Kirchhoff's loop law
  • Basic knowledge of electric potential and voltage
  • Familiarity with circuit components: battery, switch, and resistor
  • Ability to define reference points for measuring electric potential
NEXT STEPS
  • Study Kirchhoff's laws in detail to understand circuit analysis
  • Learn about electric potential difference and its applications in circuits
  • Explore the concept of reference points in electrical measurements
  • Investigate the behavior of resistors in DC circuits over time
USEFUL FOR

Students studying electrical engineering, physics enthusiasts, and anyone seeking to understand basic circuit analysis and electric potential concepts.

chris_0101
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Homework Statement


Consider the image and assume that the switch has been open for a long time. Note that the switch is supposed to be between the battery and the resistor on the top straight segment, which is not shown in the image.

http://www.sciencebuddies.org/science-fair-projects/project_ideas/Elec_img160.jpg

Also consider the initial electric potential to be V_o

a) What is the electric potential before and after the battery, switch and resistor?
b) What is the potential across the resistor
c) What is the electric potential at all points (i.e before and after the battery, switch and resistor) immediately after the switch is closed?
d) What is the electric potential difference across the resistor immediately after the switch is closed
e) After a long time after the switch has been closed, what is the electric potential at all points and what is the electric potential difference across the resistor?

Homework Equations



Kirchhoff's loop law:

ΔV_loop = 0

The Attempt at a Solution



I am having some trouble understanding the concept and I am looking for a second opinion towards my responses toward these question.

a) Since the current is broken, there is no change in electric potential (no voltage drop) therefore, before and after the battery, switch and resistor should all be 0

b) Likewise, the electric potential difference across the resistor should be zero

c) Immediately after the switch is closed, from the battery to the point before the resistor, the electric potential should be equal to V_o. After the resistor to the point back to the battery, the electric potential should be 0

d) The electric potential difference will be -V_o

e) After a long time, there should be no change, therefore the answers should be similar to c and d.

Thanks for the help.
 
Last edited by a moderator:
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chris_0101 said:

Homework Statement


Consider the image and assume that the switch has been open for a long time. Note that the switch is supposed to be between the battery and the resistor on the top straight segment, which is not shown in the image.

http://www.sciencebuddies.org/science-fair-projects/project_ideas/Elec_img160.jpg

Also consider the initial electric potential to be V_o

a) What is the electric potential before and after the battery, switch and resistor?
...snip...

The Attempt at a Solution



I am having some trouble understanding the concept and I am looking for a second opinion towards my responses toward these question.

a) Since the current is broken, there is no change in electric potential (no voltage drop) therefore, before and after the battery, switch and resistor should all be 0
Potential with respect to what? You need to define a reference point with respect to which potential is to be measured (define two points and then determine the potential difference from one to the other). What's your point of reference for the above? Perhaps it's the bottom (negative terminal) of the battery?
 
Last edited by a moderator:

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