WEDNESDAY JUNE 11, 2008

So, today in class we started off our very productive class by going over the EFFECTS OF CHANGING MAGNETIC FIELDS : INDUCED EMF. If you need to fill in the blanks, feel free to ask anyone for them =).

We also learned about Lenz's Law which basically has to do with electromagnetic induction. We got a sheet to help us figure out how this particular law works. We can use the RHR to help us determine which way the current(s) flow. For example:

Using the RHR, our thumb acts as the "arrow" and our fingers are "rolling upwards" therefore, the currents here are going up.

We also learned about TRANSFORMERS. There are terms that are associated with transformers. These are : STEP-UP TRANSFORMER and STEP-DOWN TRANSFORMER. In a step-up transformer, the primary voltage is less than the secondary voltage, and the current in the primary circuit is greater than the current int he secondary. In a step-down transformer, the primary voltage is greater than the secondary voltage and the cuurent in the primary circuit is less than the current in the secondary circuit.

There is a ratio that goes along with transformers and it looks like this:

We also got a sheet where it is also fill-in-the-blanks and a review sheet which we will go over tomorrow.

PLEASE DO NOT FORGET : TEST ON FRIDAY !!!

[ THE LAST PHYSICS TEST OF THE YEAR LADIES AND GENTLEMEN ]