adoreapple
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'What is the light intensity when the distance from the light source is 20cm?'
I don't understand if the light intensity becomes 1/400 of the original intensity or if it becomes 1/400 only?
What about 40cm? Since it was doubled, would I say it's 1/800 of the original intensity or the light intensity becomes 1/800?
I'm really confused on this, can someone help?
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0ptics
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(Original post by adoreapple)
I don't understand if the light intensity becomes 1/400 of the original intensity or if it becomes 1/400 only?
What do you mean by ‘original intensity’ here?
(Original post by adoreapple)
What about 40cm? Since it was doubled, would I say it's 1/800 of the original intensity or the light intensity becomes 1/800?
Over here, the implication is that the original intensity is 1/400. Hence, the new light intensity can’t be 1/800th of the original as you would multiply both of the numbers, giving you 1/3200, which is obviously incorrect. Besides that, it seems that you’re aware of the inverse square law, which is all you would need to answer these type of questions, IMO.
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