Physics paper 3 doubts

[DowntownCrew]

Hello everyone ,

this paper 3 is so confusing.

Here is my question in this paper :

http://www.xtremepapers.me/CIE/Cambridge IGCSE/0625 - Physics/0625_s09_qp_3.pdf

4. a.i and a.ii - how did they get those values
5. a.ii , b.i and b.ii - I couldn't find formulas for those in my book can anyone write them for me please

I appreciate your help , at least with these thanks buttons

 

[beroo1995]

for 4 a(i) u will redraw the lines joining a and b with the truck by ur new scale 8cm and 4cm and by a compass u gotta measure A to vertex and stand ond b and draw and arc and make it again by measuring b to vertex and drawing an arc from a ,,arcs will meet join it wit vertex and measure
ii)ur measurement * 500,,direction is already given 30 degrees

 

[zaisha54]

oct nov 2010 ppr variant are so difficult and different hopefully we wnt gt nythn lyk tht 2mro

 

[DowntownCrew]

What about sine ? I'm making mistake somewhere ;

it says calculate speed of medium if speed of light is 3 x 10 ^8 and refractive index is 1.49 and when I apply formula I get something like 0.58122..
What is missing in my calculation ?

n= speed of light / speed of medium

1.49 = 3 x 10 ^8 / s.o.m.

s.o.m. = sine(3 x 10 ^8) / 1.49
= 0.5812251032

Please ??