… continued from here.
*SELF POWERS UP*
Keep Calm And Shade Well
Exhausted from helping to prepare four intensive days of Science MCQ workshops, I slumped against my chair at The Temple.
After running around to ensure every student in these small, cosy classes gets the necessary attention, material, and of course the food that everyone’s raving about, I’m quietly confident that they’ve all been 传受-ed the necessary 功力, foundational & conceptual knowledge for the last, last leg of their epic O Level journey.
Speaking of which, the first of this week’s shading aka tikam-tikam exercise should have ended just this morning …
The list of workings and explanations for each of the answers (where applicable) have been compiled!
Latest version: 1.1: Q28 – corrected typo in mole calculation. Mole ratio of HCl to H₂ should be 2 : 1 (instead of 1 : 1) *bleah*
Access here by clicking the 
button (if you haven’t yet done so).
Do they tally with yours? As usual, please, please leave a comment should you spot any mistake in the solution.
Note: If you are taking Physics/Biology or Chemistry/Biology, the set of Physics/Chemistry MCQs in the relevant section of your paper should be exactly the same.
7 Comments
曜
日
Do you have it for science biology section?
曜
日
Hi Ms Loi, really appreciate your effort in doing up the suggested answers for the relevant subjects. Just wanted to enquire about Qn 12(Phy). Why can't the answer be B? I mean first when the light ray enters the glass block, it refracts towards the normal. Then it goes back out into air so it refracts away from the normal. How can we assume that the angle of incident in the glass block is greater than the Critical angle? Once again thanks for the answers. Cheers 🙂
曜
日
@Navin: The Temple's Physicist says ...
"It's given in Q12 that the critical angle (c) for light in glass is 42°.
Since it's a rectangular glass block, the first and second boundaries are perpendicular to each other so by the sum of angles in the right-angled triangle (see diagram below), the angle of incidence (i) at the second boundary is 50°
Since i > c, total internal reflection occurs at the second boundary.
P.S. Even if we suppose total internal reflection doesn't take place at the second boundary, your "suggested" answer should have been A (instead of B) since, as you mentioned, the exiting ray of light should refract away from the normal (similar to light rays through a prism)."
曜
日
@Miss Loi: Oh wow I see his/her point. Either way, I'll get this qn wrong due to my carelessness. Thanks Ms Loi and the temple's Physicist for your respond!
曜
日
when is the suggested answer for pure physics paper 1 gonna be released ?
曜
日
Mrs loi for q 6 how can u assume that the water is ablr to reach up to 400 m
曜
日
@jodan chin wei liang: The Temple's Physicist says ...
"You mean 40 m?
The reservoir and the tank are exposed to the same atmospheric pressure, and since pressure in a liquid depends only on the vertical height of the liquid column, the level of the water in the reservoir and the pipe is the same.
Actually, the reservoir and the pipe connecting it to the water tank can be considered as a gigantic U-tube with both ends exposed to the atmosphere."
P.S. It's Miss Loi not Mrs Loi 😛