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struggling with a logarithm revision question on radioactive decay: can anyone help?

kbkjbj
(edited 8 years ago)
Reply 1
Avatar for Sam00
Sam00
OP
19
I literally just put 4e^-0.2t in my calculator :s-smilie:
Reply 2
Avatar for Hōseki
Hōseki
14
Original post by Sam00
The mass kg of a radio-active substance remaining in a sample t years after starting timing is given by theequation 'x = 4e^-0.2t'

a) What was the mass at the start ofthe timing?

b) Find the mass left after 5 years

So far I have only worked out some of (a) and got an answer of 3.275kg, which I think is incorrect :frown:


This is A level Chemistry right?
I've never done A level chemistry but could you do when t=0 to get an initial mass of 4kg...
I believe you could also make a graph.
(edited 8 years ago)
Reply 3
Avatar for Hōseki
Hōseki
14
Ahh it looks like chemistry, I'm doing my AS's atm so I'm not familiar. After checking the graph for the equation, I believe the answer to part b is 1.5kg.
Reply 4
Avatar for Zacken
Zacken
22
Original post by Sam00
I literally just put 4e^-0.2t in my calculator :s-smilie:


What is it with you making these threads and then deleting all your posts and editing your OP? Do you have a reason for it?

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