ICSE − Q & A

If its given to find the focal length when power is -2D, will the answer be in negative since it is a convex lens or what?

1) At which points does resonance is heard (i read somewhere there are 3 situations etc.)
2) is frequency directly proportional to square root of radius or  proportional to  of radius ?
3) Factors affecting Critical Angle. (i think refractive index and wavelength of light is appropriate but in my book instead of R.I. temperature is given)

in physics,which chapters is most important?

how can i make coefficient of friction 0?

If there are two guitars which have the same frequency and amplitude how can they be differentiated?(The first thought that stuck me was that their quality can differentiate them but is quality different for the same instruments?)

Anyone here from last year? If so, HIHIHIHIHIHIHIHI! So good to see you again. Man the nostalgia when I look at this page again. Seeing Sam back at his motivational posts. Good to see Albert Einstein ;)
To all those who are giving their boards this year. Put in all your efforts in it. Its your time because apna time aayega. Dont let anyone else take this opportunity away from you. Its your time to shine. It'll all get over soon and you'll back and see what a beautiful journey it was. Trust me it will all be great! With hope in your heart and determination, go ahead-- PAPER MEIN FAAD DAALNA! Aisa likhna ki examiner check karte karte hil jaaye. 
Love,
Your senior,
Z.

A man having a box in head climbs a slope and another man  having an identical box walks the same distance on a levelled road.Who does more work against the force of gravity and why? (ICSE question)

Endothermic chemical reaction? 
Energy change

In which circuit is the current more: series or parallel?

Please can somebody solve Q 8. (c) 
https://www.respaper.com/ruaanb999/6630-pdf.html