Monday, June 30, 2008

Current of Electricity

Circuit Construction Kit

http://phet.colorado.edu/simulations/sims.php?sim=Circuit_Construction_Kit_DC_Only

Extra Reading

http://www.glenbrook.k12.il.us/gbssci/Phys/Class/circuits/circuitstoc.html

Wednesday, April 30, 2008

EM Waves

If you have any questions please post accordingly...

SPEED TEST
















Some Observations

  • EM wave travels at the "speed of light", please understand that visible light itself is contained within the EM spectrum. It is more appropriate to state 3.0 x 10^8 m/s in vacuum.

  • Q3, most of you understand that when frequency reduce, wavelength will increase, however they are not in a linear relationship. and the graph (graph a) should not touch x and y axis.

  • Students like to write shortest "frequency" and longest "frequency" which is inappropriate, use lower or higher instead.

    1001


    TYS


    ASSIGNMENT


    WORKBOOK

Light

If you have any questions please post accordingly...

SPEED TEST

1001


TYS


ASSIGNMENT


WORKBOOK

Sound

If you have any questions please post accordingly...

SPEED TEST
1. D
The is no medium in outer space for sound to travel
2. B
The particles inside a solid are closely packed, thus allowing the transfer of vibrational energy to be faster.
3. C
Human’s audible range is 20 Hz to 20kHz.
4 . B
Satellite does not communicate using sound waves
5
B
Time to travel across room = 0.060 s / 2 = 0.030 s
Distance = 330 x 0.030 = 9.9 m
6. C
Increase frequency of teeth hitting card to increase pitch
7.
C
Higher pitch implies higher frequency , more waves generated per second
8. B
Reflected wave has the same wavelength but different velocity due to the change in direction. The amplitude will be lower.
9. A
All electromagnetic waves are transverse wave
10. B
1st echo = (330 m x 2) / 330 ms-1 = 2.0 s
2nd echo = (660 m x 2) / 330 ms-1 = 4.0 s
Therefore time interval is 2.0 s

1001



TYS


ASSIGNMENT


WORKBOOK

Electrostatic

If you have any questions please post accordingly...

SPEED TEST
1. D
The Styrofoam balls will be charged with the same charges as the rod and each other
2. B
Only negative charges can move
3.
B
A: electric
C: magnetic
D: magnetic
4. A
An earthed object will allow excess charges to flow away to earth and leave the object uncharged.
5.
C
R: charges in the sphere that has the same charges as those in the rod are repelled away from the rod.
P: the repelled charged flows away from the sphere through the earth link.
Q: no more charges can flow to or from the sphere
S: the charges in the sphere are spread evenly
6. B
Field lines of like charges will push away from each other.
7. C
Like charges repel

1001


TYS


ASSIGNMENT


WORKBOOK