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zaheer mushtaq

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DOESNT WORK

kenny

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good luck those doing this test tomorrow

Adel Quntar

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thank you kenny

Chloe Allan

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this is a god send thank you 

safa

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on slide 27  you got the arrows the wrong way round. When they are emitted they are going up the levels so the arrow will go up and when they are absorbed then they'd go down the level so the arrow will go down. I did a past paper and I did what you did and got the answer wrong.

Rose

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sorry safa but you are wrong.

because for emission the arrows should be pointing down and for absorbtion the arrow should be pointing upwards.