SPM tips: Learn how to Apply..

Learning application of each physics concept, principles or law is vital in order for u to do well in paper 2 section A,B &C. U should attempt at least 1 section B/C question every day..if u couldn afford to do it, at least do plenty of questions on sect A,B & C every week.

Some might asked ..what is actually a physics concept??
Pressure, impulsive force, momentum, total internal reflection are examples of physics concept that we learned in form4. Basically in SPM, for each concept u had learned, u must at least be able to describe its application.
For example..lets recall about total internal reflection..

In order for total internal reflection to occur, there are conditions need to be obeyed:
1. Light must travel from an optically dense medium to a less dense medium ( e.g from glass to air) 
2. incident angle (i) > critical angle (c)





Once u fully understood the whole concepts..its time to know where u should apply it. For this one, we can apply it in fibre optics. Thus its a must for u to describe how fibre optics work  based on total internal reflection concept. This video lecture might help u to understand it better..



If u wanna know more detail about fibre optics, u should watch this!

Are u studying last minute??

According to Charles Law,under constant volume when the temperature of the gas increase..its PRESSURE increases as well. The higher the temperature, the higher the pressure.

Yeah the hypothesis is so true epecially when we 're moving towards August 2010...The temperature is rising, day by day..& most of the form5 students are started to feel the heat. To make it worst..the PRESSURE is mounting as high as mount Everest . One of my student said.."Sir, i rasa nak muntah everytime nak revise..so many things to cover.sejarah lah..add maths, chem,bio..not to mention physics..
I answered him.."well thats the price for studying last minute :) " So if u are a form4 who accidentally reads this post...i hope u'll make a better preparation for 2011.

So  the big question mark now is how to study last minute???  Is it possible to get good marks??
For me its very subjective, it depends very much on how u handle the mounting pressure. I even had a student who fainted after knowing a BAD trial results..coz if u did it badly in trial, u have about a month to recover. It sounds so frightening right ;) but some of u couldnt be bothered coz at the moment they have this 'tak apa' attitude.


Let's imagine that u are watching a football match. There's only 5 minutes left before referee blow the final whistle. Suddenly u can see players of both team are so energetic. They start to work as a team.. chasing and passing the ball accurately. They are very focused & determined to get the winning goal. Finally the ball touches one of the net in a dying moment and a group of players chasing the goal scorer. Meanwhile the other team lie down on a grass with despair. It all happened in a very last minute of the game..

anyway ..Is it possible to 'score' if we study last minute??

If u analyse the football match.. One team managed to do it and the other one has failed.The same results goes to  last minute study.
So if u are doing last minute revision, make sure u stay focus & keep your mind in a positive mode.
Having study group also will help..as in a football match, u'll work better if u help each other. In football the coach helps them to set things right and for u guidance from teacher/tutor will be helpful..but its all rely on how good u are in handling the situation. The main principle for effective last minute study is to leave everything behind and set your study as your only priority. You can leave your problems with your friends, family and even forget about you don't even have a time to 'FACEBOOK' and play PS2. In the end, if u think positive..u can definitely make it!
Here some interesting tips for those 'last minute' students

SPM Physics: Logic gates

Yesterday i teach one of my weakest student   logic gates concept. He is the type who has problem to understand physics concept properly. Somehow, when i showed him a concept of logic gates, he tends to be addicted doing logic gates exercises... This shows that he is actually good in logical thinking.

Logic gates is actually a very simple concept learned in Electronics. In fact i can say that it is one of the easiest subtopic provided if u are able to think 'LOGIC' :)
However u need to understand the following basic logic gates i.e NOT,AND,OR,NAND and NOR.
U must be able to construct the truth tables for those gates. Truth table helps us to undderstand the behavior of the logic gates. In other words, it shows how the input of a logic gates relate to its output.

Usually students a are a bit blurred on this topic coz they wondered what is actually  '1' or '0' means?
keep in mind most of computerised devices work on electrical flow where a HIGH voltage is considered as '1' and LOW voltage as '0'. Logically, it is sorts of a switching system which requires some inputs in order to produce an output.



In SPM, u need to practise lots ofpaper2 questions on application of logic gates. Usually the question can be tricky..so u must really understand the condition explained in the application.
When actually they apply this logic gate concept??

Well i can give u a simple example.. if u used to wash your clothes using washing machine..we can create a LOGIC input for the machine which looks like this:
to rotate the motor, we need to fill in the water untill to a certain level. Once the water rises to that level..the input will be '1'... but some how it still not rotated...kenapa ya? Ops, may be you lupa nak tutup the 'top cover'. Here where the logic gates play its role..the rotating motor represents the output  which depends on the input of the water level & the 'top cover' position. So it needs both input to be '1', then baru dia rotate..
Thus we can use AND gate in this application.

U can Watch this video to improve your basic understanding on logic gates

Transistor as Control Switch

Today i'm going to continue our discussion about light control switch by using transistor & LDR.

Before we go further, firstly u must understand the characteristic of LDR?
LDR is a type of resistor known as Light Dependent Resistor which is very sensitive towards light.
Important point about LDR that u MUST remember:
In a BRIGHT condition, its resistance DECREASE
In a DARK condition, its resistance INCREASE.

Now lets have a look at the circuit below, describe what happen at NIGHT???
At night,

• LDR's resistance increase much higher than the fixed resistor,
• A higher voltage is supplied across the LDR,
• This increases the flow of base current and switch ON the transistor,
• The bulb lights up

So what if we want to switch ON the bulb in the morning & close it at night?
Its simple, u just need to change the position between the LDR & the 10k fixed resistor.

The same concept applies in Heat Control switch, except instead of using LDR we use THERMISTOR.
Again, its important for u to memorise the chracteristic of a thermistor, i.e;
HIGH temperature - Resistance DECREASE
LOW temperature - Resistance INCREASE

SPM: Transistor

This topic is a bit tricky, coz in SPM we didnt learn the actual details about transistor working principle and u   need to memorise certain facts. In order to understand a transistor, firstly u must get  to know its structure & terminal. Transistor has 3 terminals, i.e a base, collector & emitter terminal. There are two type of transistor, please make sure u memorize the different between them.

The first type is called N-P-N:

The second type is P-N-P:
Main function of a transistor is to amplify small current.So its a must for u to explain how does a transistor amplify the current.




Transistor as Current Amplifier:
Transistor is a component which relies on the current that flows in its base terminal.
A small changes in base current (Ib) causes bigger change in collector current (Ic).


The analogy is simple, if u attend  morning assembly in school..usually the teacher was talking using a microphone. What actually causes the teacher's voice become louder?? Is it the microphone alone??
Actually..its the amplifier which has a transistor that did the job to amplify the voice.
Please make sure u refer your reference book on its circuit arrangement as well as its experiment.

Transistor as a switch:
This part is important in SPM..u must be able to understand and memorise its circuit arrangement.
To switch ON the transistor, we need to have:

• a higher resistance in the base-emitter circuit 
• this causes a bigger voltage dropped across the resistor in base-emitter circuit
• In the end there's enough current flowing thru the base terminal to switch ON the transistor

i'll discuss detail abt this soon.....to be continued