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Different Converging Lens Ray Diagram questions

Evan Toh

Oct 241 min read

Different Converging Lens Ray Diagram questions

Drawing ray diagrams for converging lens come in many forms. But the basic concepts needed are the 3 rays (which have rules to follow) to...

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2010SPP2Q12 Fuel gauge using variable resistor

Evan Toh

Oct 221 min read

2010SPP2Q12 Fuel gauge using variable resistor

Solutions: As the fuel level drops, the float which stays on the fuel surface will descend. The rod which is attached to the float will...

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Using P = I^2R and P = V^2/R to explain which component uses the highest power or energy.

Evan Toh

Oct 211 min read

Using P = I^2R and P = V^2/R to explain which component uses the highest power or energy.

Instead of P = IV to explain, it might be easier to explain using P = I^2R when the components are connected in series where current I is...

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When a thermistor is connected in series with a fixed resistor, how to explain the p.d. varies as resistance temperature changes?

Evan Toh

Oct 211 min read

When a thermistor is connected in series with a fixed resistor, how to explain the p.d. varies as resistance temperature changes?

When two components are connected in series, where one is a fixed resistor and the resistance of the other can vary (e.g. thermistor,...

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2012PPp1q7(c) - Determine the p.d. between points A and C

Evan Toh

Oct 210 min read

2012PPp1q7(c) - Determine the p.d. between points A and C

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2012PPp2q07 - Find the p.d. across A and C

Evan Toh

Oct 151 min read

2012PPp2q07 - Find the p.d. across A and C

Instead of the usual finding of potential difference across a component, in this question, you are required to find the p.d. across two...

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Lens – Complete the rays S and T as they pass through the lens

Evan Toh

Sep 301 min read

Lens – Complete the rays S and T as they pass through the lens

To do similar questions, it is important to know the 3 rays which have rules to follow in order to locate the image. Look through the...

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2021SPp2q8 - Which appliance uses most energy (using P = V^2/R to explain)

Evan Toh

Jan 311 min read

2021SPp2q8 - Which appliance uses most energy (using P = V^2/R to explain)

Resistors may be connected in series or parallel. When asked which resistor has higher power (hence higher energy), in general we will...

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PP2017Q11 Using P=I^2R and P=V^2/R to explain which has higher power

Evan Toh

Jan 311 min read

PP2017Q11 Using P=I^2R and P=V^2/R to explain which has higher power

Resistors may be connected in series or parallel. When asked which resistor has higher power (hence higher energy), in general we will...

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Total Internal Reflection (TIR) example 01

Evan Toh

Dec 31, 20231 min read

Total Internal Reflection (TIR) example 01

Solutions: a) Refraction b) 48.6o c) c = 41.8o e) 70o d) Total internal reflection has occured, as the angle of incidence is...

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Evan Toh

Dec 31, 20232 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...

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PP2008Q11OR Thermistor in series with fixed resistor, explanation on pd and graph

Evan Toh

Dec 31, 20231 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...

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Total Internal Reflection (TIR) example 02

Evan Toh

Dec 31, 20231 min read

Total Internal Reflection (TIR) example 02

Solutions: a) 38.8o b) 41.8o c) 51.2o . The ray does not emerge as total internal reflection has occurred. The angle of incidence is...

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2017PurePhyP2Q5 Two points on the rope wave with displacement-time graphs given

Evan Toh

Dec 31, 20231 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...

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Boy on spring board - Moments Question using Simultaneous Equations

Evan Toh

Dec 1, 20231 min read

Boy on spring board - Moments Question using Simultaneous Equations

Note: Non-uniform plank means the CG of the plank is not at its centre a) Find the weight of the boy. b) How far is the centre of gravity...

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Car A and Car B – Find the time one overtakes the other

Evan Toh

Nov 30, 20231 min read

Car A and Car B – Find the time one overtakes the other

The speed-time graph of Car A and Car B, along a straight road over 4 seconds is shown below. a) Calculate the acceleration of Car A and...

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Modification to ammeter to measure bigger current

Evan Toh

Nov 30, 20231 min read

Modification to ammeter to measure bigger current

Sensitivity of the ammeter means that how small a current the ammeter can measure. Example, if the original set up is 0.2 A per division,...

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Dynamics and kinematics: Force-time graph, find frictional force

Evan Toh

Nov 30, 20231 min read

Dynamics and kinematics: Force-time graph, find frictional force

A 10 kg box is initially at rest on a rough horizontal surface and a horizontal force is then applied to it. The force varies as shown in...

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Minimum force to lift a drum over a step (different examples)

Evan Toh

Nov 30, 20231 min read

Minimum force to lift a drum over a step (different examples)

Given that the mass of the drum is 20 kg. What is the minimum force, F, required to just movee th drum off the ground? (Assume uniform...

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Ball thrown vertically up from building and falls to ground

Evan Toh

Nov 30, 20231 min read

Ball thrown vertically up from building and falls to ground

A rock is thrown vertically upwards with a velocity of 29.4 m/s from the top of a building 78.4 m high. After how long will the rock...

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