CaiHongRainx,
Nope I wasn't, but I discussed most of the questions with most
of my teachers and received rather similar feedback.
Qn 1: TYS once have this qn, and their answer is
A.
Aye brother, if the answer is
A in the TYS, then I probably would agree with you then.
=)
Qn 7: If it’s a cynlider instead of trapesium, the pressure
will still be the same? (According to the formula)
Yes. The breadth of the cylinder
does not matter. Only the height, density and gravitational
pull.
Qn 20: You meant A instead of B right?
Yes, thanks for the
correction!
Qn 22: Why loudness at P will increase?
When the amplitude
is reduced, complete cancellation will not occur.
Thus, the minimum loudness will thus become louder.
Qn 25: I understand that the diode has the graph. But for
thermistor and LDR, which are semi conductors, if you
consider the higher end of the portion, it does look like the graph
of forward-biased of the diode. So it can be a thermistor or
LDR also.
For diodes, there is this thing
called the saturated current, where there will be a straight line
after the 'curve'. Thermistor or LDR does not possess this
capability, even at higher ends, because it will still result in an
exponential graph.
Diode Graph:
http://www.electronics-for-beginners.com/pictures/diode_graph.PNG
Thermistor (which will be the same
for LDR) Graph:
http://www.passmyexams.co.uk/GCSE/physics/images/Graph_for_Thermistor.jpg
This question was a little bit
unfair because those who took NTU's H3 Semiconductor Physics and
Devices will have an advantage in this.
Qn 27: Why is it D?
Area of Q is half of
that than that of Area P.
Length of Q is double than that of
Area P.
Thus, resistance for Q will be
four times than that of P.
Resistance of Q will be 16
Ohm.
Total resistance = 16 + 4 = 20
Ohms, hence D.
Qn 32: Q = It . So for the negative part of the graph, won’t the
Charge, Q be -ve as well?
Nope it won't, because this is the
*net* amount of charge. The net charge will just simply fall, and
reach zero.
Qn 37: Why it isn’t A ?
To start off, this isn't your
fault to think that it is A because Cambridge isn't clear in
this question. The shaded portion actually means electrons. At room
temperature, the electrons at the donor level will be excited to
the conduction band easily (in fact, nearly all of the electrons in
the donor level). Thus, there will still be electrons in the
conduction band at room temperature.
Qn 40: Q emit 1 alpha particle, why does it have the same nucleon
number? I feel that answer should be D cause R emits all beta
particles, thus the nucleon number won’t change. Q should have the
same proton number also
My apologies, I realised I typo
hahaha! Yes it is D! =)
