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# A-Level Physics - [Question]

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1. How many electrons flow past a point each second in a 5.0mA electron beam?
I used I=Q/T
I = 0.005 A
Q =
T = 1
so Q = 0.005 C
right?
2. That seems correct.
3. (Original post by JustasB)
That seems correct.
I got the answer it was just telling me it was wrong as I had

Thanks
I got the answer it was just telling me it was wrong as I had

Thanks
The answer was to 2 significant figures, so the answer of 3.13 is correct but it should be rounded to the correct number of significant figures.
5. (Original post by JustasB)
The answer was to 2 significant figures, so the answer of 3.13 is correct but it should be rounded to the correct number of significant figures.
Thanks
Do you have an idea on this question:
Alpha particles have twice the charge of an electron. What is the current caused by a radioactive source which emits 3000 alpha particles per second, to 3 significant figures?

First I found out the charge which is 3.2*10^-19 (For one alpha particle) then I multiplied it by 3000 to get charge for 3000 alpha particles which is 9.6x10^-16 C now i used I = Q/T
so I would equal 9.6 x 10^-16 aswell but i'm not sure what to do now or what i done wrong as this answer is incorrect
Thanks
Do you have an idea on this question:
Alpha particles have twice the charge of an electron. What is the current caused by a radioactive source which emits 3000 alpha particles per second, to 3 significant figures?

First I found out the charge which is 3.2*10^-19 (For one alpha particle) then I multiplied it by 3000 to get charge for 3000 alpha particles which is 9.6x10^-16 C now i used I = Q/T
so I would equal 9.6 x 10^-16 aswell but i'm not sure what to do now or what i done wrong as this answer is incorrect
oh wow, it is correct just not to 3 sig. fig. once again.
Keep making the same mistake, my bad!

Edit:
Do you know if i have to always use correct sig. fig. in the exam? (AQA if it helps)
oh wow, it is correct just not to 3 sig. fig. once again.
Keep making the same mistake, my bad!

Edit:
Do you know if i have to always use correct sig. fig. in the exam? (AQA if it helps)
Use the same number of significant figures as given in the question.
8. (Original post by JustasB)
Use the same number of significant figures as given in the question.
okay thanks

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