This discussion is now closed.
Check out other Related discussions
- IGCSE single award vs double award science
- Exams anxiety
- 16+ Exam
- Can I study economics/computer science at uni without maths a level?
- Are my gcses good enough to do eng lit at cambridge
- Physics vs further maths difficulty
- A-levels for Ivy League Admissions
- Need help picking a levels
- A levels Choices
- should i self study alvl further maths over summer
- Don't know if I should keep doing 4 A-Levels
- Urgent Help!! MEDICINE AND GCSEs
- Should I repeat year 13 maths?
- I'm a former GCSE Student. Ask Me Anything
- Should I remark ?
- History
- Cambridge GCSES - are they too low???
- help me consider a level options! (thoughts/advice)
- IAL repeats cash in.
- GCSE
PHY 4 and 5
AAAAAAAAHHHHHHHHHHH, some1 help me. Whats a stopping potential? cant seem to define it easily and all the papers i have tried looking at have wierd questions. Can sum1 give me a definition and the context it will be found in, in a question.? Thanx
scaredashell
AAAAAAAAHHHHHHHHHHH, some1 help me. Whats a stopping potential? cant seem to define it easily and all the papers i have tried looking at have wierd questions. Can sum1 give me a definition and the context it will be found in, in a question.? Thanx
is the minimum reverse potential applied across the emitted electrons in order just to stop them all
basically...it's when you have a circuit with a cathode and an anode, where the cathode is made of a substance which emits electrons via the photoelectric effect. By illuminating the cathode with UV light of the right frequency, photoelectric emmision occurs and the fastest electrons also gain enough kinetic energy to go to the anode.
However, the anode is made negative as well to repel the incoming electrons and is also connected to a potentiometer. First use a low voltage and all the electrons reach the anode. However when you increase the voltage across the anode, it becomes more positive and repels the high kinetic energy electrons. Soon, none of the electrons will reach the anode and you will get a zero reading on a picoammeter connected to the circuit.
What does this mean?
Well, the instance that the electrons with the highest KE (ie. ones at the surface of material) do not reach the anode, the voltage reading on the potentiometer is the force stopping the electrons.
Therefore.... ½mv² lost = qV gained (electrical energy),
(where V is the stopping potential, the voltage across the anode which prevents the highest KE electrons from reaching the anode)
So stopping potential is proportional to the KE of the fastest electrons in a sample.
Hope that helps
»»»»»»»»»≡≡∂√≠≠≡≡√±³∫³≈√°÷±³²∫
However, the anode is made negative as well to repel the incoming electrons and is also connected to a potentiometer. First use a low voltage and all the electrons reach the anode. However when you increase the voltage across the anode, it becomes more positive and repels the high kinetic energy electrons. Soon, none of the electrons will reach the anode and you will get a zero reading on a picoammeter connected to the circuit.
What does this mean?
Well, the instance that the electrons with the highest KE (ie. ones at the surface of material) do not reach the anode, the voltage reading on the potentiometer is the force stopping the electrons.
Therefore.... ½mv² lost = qV gained (electrical energy),
(where V is the stopping potential, the voltage across the anode which prevents the highest KE electrons from reaching the anode)
So stopping potential is proportional to the KE of the fastest electrons in a sample.
Hope that helps
»»»»»»»»»≡≡∂√≠≠≡≡√±³∫³≈√°÷±³²∫
Related discussions
- IGCSE single award vs double award science
- Exams anxiety
- 16+ Exam
- Can I study economics/computer science at uni without maths a level?
- Are my gcses good enough to do eng lit at cambridge
- Physics vs further maths difficulty
- A-levels for Ivy League Admissions
- Need help picking a levels
- A levels Choices
- should i self study alvl further maths over summer
- Don't know if I should keep doing 4 A-Levels
- Urgent Help!! MEDICINE AND GCSEs
- Should I repeat year 13 maths?
- I'm a former GCSE Student. Ask Me Anything
- Should I remark ?
- History
- Cambridge GCSES - are they too low???
- help me consider a level options! (thoughts/advice)
- IAL repeats cash in.
- GCSE
Latest
Trending
Last reply 4 days ago
Edexcel A Level Politics Paper 1 (9PL0 01) - 21st May 2024 [Exam Chat]Trending
Last reply 4 days ago
Edexcel A Level Politics Paper 1 (9PL0 01) - 21st May 2024 [Exam Chat]
