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2010SPp1q12 Lens - focal length definition
Answer: Option C Focal length f is the distance between the focal point and the centre of the lens (optical centre) . Note that only...
Evan Toh
Jan 1, 20241 min read


2008PPp1q15,2017PPp1q15– Pressure constant, rate of collision decreases
When gas in piston and heated but pressure remains constant. It is easier to explain in terms of the average force acting on a unit area....
Evan Toh
Jan 1, 20242 min read


2021SPP1Q15 Electric field lines between the two charges
Answer: Option D View the video tutorial for the explanation
Evan Toh
Jan 1, 20241 min read


2013SPp2q9 – Pressure and Moment
Solutions: (a) (i) A bigger force than F can be obtained due to the lever system and hydraulic system . Lever system: Applying...
Evan Toh
Jan 1, 20242 min read


SP N2007 P1 Q16 – Which events will cause the fuse to blow?
An electric cable contains three wires live, neutral and earth. The cable is correctly wired to a plug which contains a 3A fuse. The...
Evan Toh
Jan 1, 20242 min read


Evan Toh
Jan 1, 20241 min read


2004PPp1q15 - Volume of bubble at bottom of lake (P1V1 = P2V2)
Answer: Option A Since the air bubble is enclosed, PV at A is equal to PV at B. PAVA = PBVB (Patm + Pwater) VA =...
Evan Toh
Jan 1, 20241 min read


PP2008Q11OR Thermistor in series with fixed resistor, explanation on pd and graph
As both the fixed resistor and the thermistor are connected in series, the sum of potential difference across them will be equal to the...
Evan Toh
Jan 1, 20241 min read


PP N2010 P1 Q4 Two objects same size and shape but one is heavier. Motion when both released
Solutions: Option C When a body is released from rest, the only force acting on the body is its weight due to gravity . Both bodies...
Evan Toh
Jan 1, 20241 min read


Identifying what lens, focal length and image from 2 rays – PP2010P1Q23 and SP2014P1Q11
These 2 questions are actually the same. Q23 is from 2010 Pure Physics P1 while Q11 is from 2014 Sci Physics P1. Take a look at these 2...
Evan Toh
Jan 1, 20241 min read


Evan Toh
Jan 1, 20241 min read


Determine the motion of the particles on transverse wave
Instead of imaging how the particles will move and guess their motion, there is a technique which can help you to determine that. In...
Evan Toh
Jan 1, 20241 min read


2013SPp1q17 What is the new P when V across resistor is doubled? Similar 2018PPp1q31
Answer: Option C View the videos below to learn how to solve it. There are more than one method. Alternatively, you may put values to...
Evan Toh
Jan 1, 20241 min read


Evan Toh
Jan 1, 20241 min read


2017PurePhyP2Q5 Two points on the rope wave with displacement-time graphs given
In this this question, the displacement-time graphs are given, which are different from displacement-distance graphs. In the...
Evan Toh
Jan 1, 20241 min read


2007PPP1Q27 brightness of bulb
Solutions: Option B As lamp X is thicker and shorter , these two factors make the resistance of X lower than Y . Recall: Length...
Evan Toh
Dec 1, 20231 min read


N2007P1Q9 Pure Physics – Energy needed to pump water up a building
Answer: Option B Since water will naturally reach 40m high from the bottom of the apartment, you only need to pump the water up by a...
Evan Toh
Dec 1, 20231 min read


2004PPp1q4 2010SPp1q4 Dynamics (3rd law)
Answer: Option D Key concept here is Newton’s 3rd Law. Action equals reaction. Both trolleys are connected by the spring, hence the...
Evan Toh
Dec 1, 20231 min read


PP2010P1Q23 and SP2014P1Q11 - Identifying what lens, focal length and image from 2 rays
These two questions are actually the same. Q23 is from 2010 Pure Physics P1 while Q11 is from 2014 Sci Physics P1. Take a look at these 2...
Evan Toh
Dec 1, 20231 min read
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