Alternating Current - Keeping it Warm and Fuzzy

Physikos 2009, steve.chrystall@gmail.com

6V

1A

What does 6V mean?

What does 1A mean?

Lamp A

• The flow over the Huka Falls fluctuates between 32 and 270 cubic metres per second. On average the daily flow over the falls is 160 cubic metres per second

If there are 7 drops of water in 1cm3, how long would it take for

6,000,000,000,000,000,000 (6 million million million drops)

drops of water to flow over the Huka Falls?

(average flow rate = 160cubic metres per second)

6,000 cubic metres/second

• Time for 6 million million million drops?

6V

1A

Two lamps Identical to lamp A are placed in series

What is the brightness of lamp B compared with lamp A?

Lamp B Lamp C

a) B is the same brightness as A

b) B is half as bright as A

c) B is quarter as bright as A

How many models do we need for electricity?

LCR Circuit

VLVRVC

VS

VL

VC

VR

VR is always in phase with current

I

VL leads current by 90˚

0.01s

0.5A

Current vs time for previous LCR Circuit

Current (A)

Time (s)

If L= 20mH, calculate the Voltage at t=0s