Physics, Chemistry and Biology: Post your doubts here!

[$hadow]

Physics help needed
Can anyone help me in Part b of this question please View attachment 48123

because the radioactive material has finished decaying. the count rate remaining is the rate of background radiation.

 

[champ-student]

because the radioactive material has finished decaying. the count rate remaining is the rate of background radiation.

Part b.

 

[$hadow]

Part b.

Half life at 33 counts so 1.6 days??

 

[champ-student]

Half life at 33 counts so 1.6 days??

Yeah. Your answer is right but how?
there's something im missing

 

[$hadow]

Yeah. Your answer is right but how?
there's something im missing

Minus background radiation (14) from initial reading(52). You will get 38. divide 38 by 2 because of half life then add background radiation again. you will get 33. Then refer to graph.

 

[champ-student]

Minus background radiation (14) from initial reading(52). You will get 38. divide 38 by 2 because of half life then add background radiation again. you will get 33. Then refer to graph.

oh..Thanks dude. You saved the day

 

[champ-student]

Can anyone help me in part C please.
Shadow
physics tomorrow

 

[phyo phyo]

End Q of the wood will be hottest because the heat is not conducted away from the source by the wood.

This can be demonstrated by using the apparatus shown in the diagram. If a piece of
paper is fixed tightly around the wood / copper joint, the paper will singe on the wood side (high temperature)
but not on the copper side (lower temperature).

Thank you very much. I got it now.

 

[phyo phyo]

Can anyone help me in part C please.
Shadow
physics tomorrowView attachment 48127

It depends on your diode connection. If your diode is forward biased when A is positive terminal, the graph will be half wave with positive cycles between 0-1 sec and 2-3 sec. Maximum voltage on reading is 3V because it is potential divider circuit.

 

[Sruhti]

Hello in S07QP3 question 3(B),
why is it that the mark scheme says ignore kinetic energy and sound?

 

[Phoenix Blood]

Hello in S07QP3 question 3(B),
why is it that the mark scheme says ignore kinetic energy and sound?

That's because the primary things the examiners are looking for in your answer is that:
a) P.E. decreases
b) decrease becomes heat

It isn't wrong to mention KE and sound, but the answer needs to focus on the energy transformations, which is mainly decrease in potential energy.

 

[Sruhti]

That's because the primary things the examiners are looking for in your answer is that:
a) P.E. decreases
b) decrease becomes heat

It isn't wrong to mention KE and sound, but the answer needs to focus on the energy transformations, which is mainly decrease in potential energy.

isn't potential to kinetic energy an energy transformation?

 

[Sruhti]

also can you help explain s10qp32 q1(b)
thanks!

 

[Phoenix Blood]

also can you help explain s10qp32 q1(b)
thanks!

Use the formula for kinetic energy , 1/2*m*v^2

=1/2*0.6*7^2
= 14.7 J.

 

[$hadow]

Can anyone help me in part C please.
Shadow
physics tomorrowView attachment 48127

have u done your part b? the answer to it should be in your part b. i am quite lost in part b but i know that u will get the answer to part c if u get part b correct.

 

[Sruhti]

ev

Use the formula for kinetic energy , 1/2*m*v^2

=1/2*0.6*7^2
= 14.7 J.

i did that too but the mark scheme says you have to subtract it from the first answer. i do not understand why

 

[Dsilentkila]

SALAMS
Does anybody have a PDF of "Islamiyat A core text for OLevels" ?
Thanks alot

 

[champ-student]

Can someone tell me when this colored thingy is one the book cover

our teacher hinted exams would include this

 

[Phoenix Blood]

View attachment 48265 Can someone tell me when this colored thingy is one the book cover

our teacher hinted exams would include this

Lol How does your teacher know what will come in the Board examination? And ofcourse, if it includes the portion stated in the syllabus, things from this would be bound to come
Book cover of what?

 

[champ-student]

Lol How does your teacher know what will come in the Board examination? And ofcourse, if it includes the portion stated in the syllabus, things from this would be bound to come
Book cover of what?

lol its just school exam. nothing big