A Level Physics Paper 4| October/November 2021| Paper 41| 9702/41/O/N/21 | 9702/43/O/N/21 |Solution

[@ridzs]

Ure very good thank u❤

[@alevelandapphysics-ali]

Glad it helped

[@-omar-4214]

Shouldnt enduced emf be - at first? Opposite to change causing it? In question 9

[@alevelandapphysics-ali]

In the question it's given that at t=0 emf =0

[@-omar-4214]

​yes but it can do down just like it can go up. @alevelandapphysics-ali The question didnt state initial current positive or negative, so does that mean we can draw sin or -sin shape?

[@alevelandapphysics-ali]

@@-omar-4214 emf =BANwsin(wt) . Both should be acceptable .

[@-omar-4214]

@@alevelandapphysics-ali got it Thanks so much

[@alevelandapphysics-ali]

@@-omar-4214 Glad it helped . Feel free to ask if you have any questions .

[@cappybaraeats]

for question 1 (ii) centripetal acceleration i tot u should use the equation a= v^2/r therefore y is less than x.... why use f=ma??

[@alevelandapphysics-ali]

Because in the question it's not given that both cars have same centripetal acceleration that's reason in b(ii) we used concept of centripetal force ( resultant force ) to find out whether they have the same centripetal acceleration or not . In order to compare maximum speed of car X and car Y , we can use centripetal accleration equation becasue both cars have the same mass but using centripetal force equation is more intuitive for better understanding . Hope it helps .

[@Abc-qu5mj]

Sir in question 8 The force on PQ is an upward force. But it’s shown as downwards in the diagram used to explain the last part of question 8. Please kindly clarify this sir. Thank you sir

[@alevelandapphysics-ali]

In b(ii) , force on wire is upwards that's reason reading on Newtonmeter decreases . To explain b(iii) , I added extra figure for better understanding .

[@damodarramdoyal5890]

Thank youuu sir🙏

[@damodarramdoyal5890]

Hello sir, can you please solve the Oct Nov 2021 Paper 42. It will be very helpful for us to learn how to solve certain challenging questions. Thanks🙏

[@alevelandapphysics-ali]

I'll be uploading March 2022 42 solution in this week and I'll also try to upload ON2021 42 if got enough time .

[@GRIMREAPER-up7io]

why does the internal energy remain constant in part d ??

[@alevelandapphysics-ali]

In this case , we are assuming same change in internal energy to compare thermal energy supplied when work done is zero ( piston is fixed ) and when work is done by gas ( piston is not fixed ) .

[@alevelandapphysics-ali]

Change in internal energy is proportional to change in temperature (in Kelvins ) .

[@GRIMREAPER-up7io]

@@alevelandapphysics-ali ok thanks alot sir

[@moizahmed2904]

Q7?

[@alevelandapphysics-ali]

Q7 is about OP-AMP and op-amp is not part of new syllabus .

[@zeidbadulla6652]

pls do question 5

[@alevelandapphysics-ali]

Q5 is from old syllabus and not part of New Syllabus for 2022 and afterwards .

[@liveszain]

Sir I need your guidance please reply on Facebook 😔

[@alevelandapphysics-ali]

Okay

[@liveszain]

@@alevelandapphysics-ali I texted you on messenger with name Muhammad Zain