Videos on Lenz's 's Law

I've explained a bit on Lenz's law in previous post. Some students having problem to apply tis law..
So please clarify it b4 its too late..go & ask yr teacher or tutor..

In SPM we use this law to find the direction of induced current in the solenoid.
However lenz's law is not only about finding induced current. The following video demonstration might be usefull to describe the whole concept of lenz's law.Enjoy watching..

SPM 'A' tips: Stop Procrastinating

Most of u might realizes that one of the most common problems when studying is procrastination( suka bertangguh). We all know what we want to do and what we should be doing... but in the end we still end up spending hours doing “easier” work like watcin TV, surfing internet,doing facebook & myspace, playing 'stupid' games,or listen too much of music.
Now, nothing wrong with a little escape from time to time. But if you procrastinate too much..
dont blame others if u cant get a good results for your SPM...
U should blame urself for playing games sampai 4 hours, but spent only 1.5 hrs hours doing revision during this cuti skolah.

So.. how can you change this bad habit? Here i will only share 2 tips to help you to stop procrastinating and start appreciatin your priceless time from now on.
so these tips are very usefull for my form4 students..no honeymoon year ok :), othrwise u end up like some of those 'cool' spm candidates...
though it seems a bit late for them, its better to start to do something rather than doin nothing..

Ok..1st rule:
Stop thinking... Start doing.

A bit of planning can certainly help you to achieve what you want to achieve.
'Too much planning and thinking' tends to have the opposite effect. You always think and think and try to come up with “the perfect plan”. A plan where you don’t have to make mistakes, where you will never be rejected, where there will be no pain or difficulties. Such a thing does of course not exist. But as long as you work on what u've planned, you can protect yourself.. at least from getting 'F' :)
U can start with a simpleplan. What i mean of simple plan is go & do your study time table NOW! Then execute it..

2nd rule:
Just take the 1st STEP

Focus on taking the first step today. That is all you need to focus on, nothing else. By taking the first step you change your mental state from resistant to “hey, I’m doing this,.. it seems cool babe”. SO..You've put yourself in state where you are becoming more positive. We need this positive energy..Then you can take the next step..and another step further..untill u can do it consistantly.

As for the beginning..here i attached a few collection of midterm exam papers from Melaka.
So what are u waiting for..go & try them! .. take the very 1st step :)..no more procrastinatingg...just say TAK NAK!

SPM: Induced Current

ok.lets continue our discussion on Electromagnetic induction..
In SPM syllabus, its important 4 u to know how to determine the direction of induced current in the following cases:
i. direction of induced current in a straight wire..
u can use Flemming's right hand rule to identify the induced current's direction.
BUT remember!!!!!! we use RIGHT hand for this..NEVER use your left hand!!! Left hand is used to find the FORCE in electromagnet. We use RIGHT hand to find the CURRENT direction..and its only valid for induction. How to use this rule?? look at the diagram below

One student asked me..Sir..i'm confused ..whats the difference between left & right hand rule???
OK, to answer that question.. please notice the following comparison carefully,

Electromagnet	Electromagnetic Induction
- Use FLEMMING LEFT HAND	- Use FLEMMING RIGHT HAND
- current is needed	- Motion/force is needed
-FORCE is produced	-INDUCE CURRENT is produced
- process of making a temporary magnet	- process to generate induced EMF to generate induce current
- concept used to build D.C motor	- used to build Generator

ii.direction of induced current in solenoid
for this case u really need to understand the whole concept carefully..student always get confuse when using this law...
Ok..to determine the current direction in solenoid..we use LENZ's law. What is LENZ's law???

Lenz's law states that...
the direction of induce current is such that the change producing it will beopposed.
*******please understand this law & try to memorize it*********


Lets now apply what actually this law trying to tell us. Observe the following figure 1 & figure 2.

In figure 1:
- the NORTH pole of the bar magnet is moving into the coil,

According to Lenz's law..
- the induced current produced will flow in such a way to oppose the approaching bar magnet
- thus, the flowing induce current produces North pole on the end of coil as to repel the
approaching magnet.


In figure 2:
the NORTH pole of the bar magnet is pulled out from the coil,

According to Lenz's law..
- the induced current produced will flow in such a way that it won't allow the bar magnet leaving
the coil
- thus, the flowing induce current produces SOUTH pole on the end of coil as to prevent the
magnet from leaving.

Electromagnetic Induction

Today i wanna go back to where we've left our previous discussion on electromagnet . The last sub-topic we've discussed was about d.c motor principle.

The next discussion will be subtopic 3.3 which is one of my favorate.. its about electromagnetic induction. I like this one bcoz its like doing an illusion .Just imagine without a battery or solar power supply can we still light up a bulb?..

Usually to light up the bulb we need continuous supply of current, which we get it from batteries or solar energy. But in this topic, we dont need those batteries..all we need is a magnet.


YEah..magnet alone can produce current..but HOW??
This process is what we call magnetic induction..
By bringing the magnet closer or moving it into the coils of wire, u can produce current which is known as Induced Current...Meanwhile, the emf produced is known as induced emf.
U can actually ligt up your torchlight without any batteries....watch this


So in SPM, u must be able to
i. describe electromagentic induction... HOW??

When we move a magnet into a coil of wire,there is change in magnetic field. In other wrords, the magnetic fields are being cut which cause an induced e.m.f (electromotive force) to be produced.
An induced current flows through the wire and this phenomenon is called electromagnetic induction

To understand this better..u can watch these videos..

look!.. what happen to the ammeter reading when a magnet is brought close to the coil..




u can also download this note to get a clearer picture on electromagnetic induction.
The same concept is applied in bicycle's dynamo . The bulb lights up when u start to cycle..no batteries are needed..all u need is to continue cycling.
This is the mysterious world of magnet..it generates current when the magnetic fields being cut.
I'll discuss more about this on next post.

SPM A1 Student tips

Hi guys..

Yeah!!Its holiday season again..a Holiday mood!!
However is it Time to enjoy & relax? yeah y not..
but don't forget to revise k..coz othrwise SPM will haunt u after the school break..hopefully u'll b having a 'productive holidays'

For today's post, its worth reading this article written by one of your seniors who got an A for physics. They summarize some good tips on studying SPM physics.. enjoy reading :)

How to Study Physics for SPM?

Although I scored an A1 in Physics for SPM, I am not exactly the right person to be asked, "how did you do it?" So, I posed the question to my friend, Jasmine, instead to see what she had to say. Jasmine and I have known each other for 5 years (yes, throughout my secondary school years) but, our fathers know each other longer than that! Anyway, here is what she had to say:

Firstly, Physics is very different compared to the other subjects. Physics is one of the toughest Science subjects for many people. Physics is more to the Maths side as it is mostly calculations, formulaes and principles.. Biology is 100% memorising, Chemistry is 50% calculation, 50% memorising, Physics on the other hand is 100% calculation and formulaes. The study of Physics is very deep and it involves a lot of techincal details: heat, electricity, electronics and so forth. Every minor detail is important and that makes the subject complex and sometimes even tedious. Nevertheless, once mastered, Physics is very useful for survival purposes in our daily life.

One very important thing in Physics is understannding. You must understand what you are learning, not just memorise for the sake of exam. Physics is actually an easy subject to study. All you must know are the formulaes and principles involved.. What usually happens is the teacher will twist the questions and asked them from different angles. That is when it becomes tough. What you must remember is the basic pronciples involved. No matter how tough the question is, in the end, it will always go back to the basic principles.

I would recommend a good revision book for this subject as the school textbook alone is not enough to score. Pay attention in class and ask questions whwnever you don't understand. Do not be scared or shy to question your teachers as it is necessary for you to know in detail about Physics. For eg:
Where did the formulaes come from, how are they derived, how are the variables involved connected to each other, conversion of units and many more.

Master your calculations and make sure you choose the right formulaes for each question. This can be a problem sometimes. Physics is not a mugging subject, you cannot simply study it by the book. You must attempt questions from workbooks and do a lot of exercises. Only then you will be exposed to a wide range of different ways questions can be asked. Hence, you will be able to answer various types oy questions no matter how tough they may seem.

Interest plays a vital role in scoring in this subject. You must show keen interest in studying Physics. Most people dislike the subject as it is far more complicating then the other Science subjects. Therefore, they make no effort to master the subject.

Finally, try attempting the past year questions for Physics. Analyse the questions and topics that have come out in the previous years. SPM questions are always very similar, so chances of the same type of questions coming out every year is very high. Please take note, same type of questions, not same questions. Make sure that you are able to do all the past year questions. If so, you will not have a problem during the actual exam.

It is very important for you to understand in Physics. You MUST know what you are studying. Only then will you be able to score in the subject. Physics is not a difficult subject. I feel that it is much easier than Biology and Chemistry, bur it requires a lot of patience, interest and understanding.

NEXT, I asked her what type of reference books she would recommend. Also asked why she was very interested in the subject.

I don't know what are the reference books they have nowadays for Physics but I would recommend either Success or Focus. I found both quite good. But you can also check out the others that are there now.

I was always interested in tools and mechanical stuff ever since I was small. I love playing with my father's gadgets even now and I suppose that's why I love Physics. This is something that has to come from within I guess.

So, there you have it. Feel free to add on to the above mentioned points. One question for all of you out there, how do you spark an interest in Physics?