A level D.C circuits
Galvanometer reads 0 current.
When the internal resistance of the 2V battery increases, does the position of the sliding contact need to change?
Original post by noodledoodle
Galvanometer reads 0 current.
When the internal resistance of the 2V battery increases, does the position of the sliding contact need to change?
Galvanometer reads 0 current.
When the internal resistance of the 2V battery increases, does the position of the sliding contact need to change?
No. Because there is zero current in that part of the circuit and no current in the internal resistance and so no "lost" volts.
It would need to change if the internal resistance of the 4.5V cell were to change.
Original post by Stonebridge
No. Because there is zero current in that part of the circuit and no current in the internal resistance and so no "lost" volts.
It would need to change if the internal resistance of the 4.5V cell were to change.
It would need to change if the internal resistance of the 4.5V cell were to change.
Why will there be no current? If there is no current throught the 2V battery wouldnt there also be no current in the 4.5V battery?
Original post by noodledoodle
Why will there be no current? If there is no current throught the 2V battery wouldnt there also be no current in the 4.5V battery?
The 4.5V battery is there to maintain a steady current through the rod. This then maintains a constant pd across the rod. This pd will be about 4.5V. (The emf of the cell less any lost volts due to its internal resistance.)
Let's say for arguments sake that the pd across the rod is 4V.
The lower circuit will balance (that is, galvo current = zero) when the sliding contact is exactly half way along the rod. This is the point where the potential is 2V. The 2V across that fraction of the rod balances the 2V emf of the lower cell.
Original post by Stonebridge
The 4.5V battery is there to maintain a steady current through the rod. This then maintains a constant pd across the rod. This pd will be about 4.5V. (The emf of the cell less any lost volts due to its internal resistance.)
Let's say for arguments sake that the pd across the rod is 4V.
The lower circuit will balance (that is, galvo current = zero) when the sliding contact is exactly half way along the rod. This is the point where the potential is 2V. The 2V across that fraction of the rod balances the 2V emf of the lower cell.
Let's say for arguments sake that the pd across the rod is 4V.
The lower circuit will balance (that is, galvo current = zero) when the sliding contact is exactly half way along the rod. This is the point where the potential is 2V. The 2V across that fraction of the rod balances the 2V emf of the lower cell.
I understand. Thanks!
Quick Reply
Related discussions
- How does the variable resistor circuit provide a larger current?
- Physics GCSE question
- Confusing Capacitor question
- AQA A Level Chemistry Electrochemical Cells
- NEA game ideas
- In what circumstance would a variable resistor be unaccepted to vary voltage?
- A level physics electricity
- Computer science or electronic engineering
- Is A Level Electronics Obselete?
- A level physics Electricity question (2)
- Physics A-Level AQA
- Logic gates in Unity
- RLC circuit
- HNC electrical engineering
- physics alevel edexcel circuit question
- As temperature increases, what the hell happens to current and resistance??
- Unit 6 Micro controllers exam- Engineering btec level 3 extended diploma
- Capacitor Question (PHYS)
- Circuits Question
- Physics OCR A-level PAG 9.2
Latest
Last reply 53 minutes ago
Official University College London Applicant Thread for 2024Last reply 58 minutes ago
Can I do economics degree without a level maths?Last reply 1 hour ago
How to choose unis in UCAS application for CS undergraduate course?Last reply 1 hour ago
Rishi Sunak pledges to remove benefits for people not taking jobs after 12 monthsLast reply 2 hours ago
Got my crush's number 2 days ago and no reply yet. What could be the reasons?Posted 2 hours ago
GB News set to axe 40 jobs after channel posts heavy lossesLast reply 2 hours ago
Rwanda bill likely to be stalled at least till April after seven defeats in the LordsPosted 2 hours ago
Sunak rejects offer of youth mobility scheme between EU and UK
