Lighting up a fluorescent lamp with a Van De Graaf generator

Hi all,

Let's say i have the following:

I approach a charged-up VDG holding a fluorescent lamp. The end nearest the VDG is labelled A and the end furthest away from the VDG is labelled B. My hand is holding the lamp in the middle, i.e between ends A and B.

The region inside the lamp between A and my hand lights up. This is due to a potential difference between A (high potential) and my hand (ground potential). The region inside the lamp between B and my hand does not light up.

My question is this: IS there any potential difference between end B and my hand also? My understanding is that without my hand there, end B should also have a high potential,though not as high as A since it is further away from the charged up sphere. Since the region between B and my hand does not light up, i gather there is no potential difference between B and my hand. If that is the case, does it mean to say that B is now also at ground potential?

Thanks and regards.


Science Advisor
Homework Helper
I'd like to know the answer to this too.

Guys? :smile:

The Physics Forums Way

We Value Quality
• Topics based on mainstream science
• Proper English grammar and spelling
We Value Civility
• Positive and compassionate attitudes
• Patience while debating
We Value Productivity
• Disciplined to remain on-topic
• Recognition of own weaknesses
• Solo and co-op problem solving