IB Physics 12

Mr. JeanDecember 5th, 2014

The plan: • Video clip of the day• Internal resistance in a battery• The Tesla… if you liked the “WEEBERRR”

just wait…..• More magnetic fun!

Internal Resistance: • Systems do not like to change when in steady state.

• When a battery is not connected it’s at a steady state; however when we start get current to flow we need to push the current down the wire.

• In a closed circuit we see that the wire is connected back to the battery. Thus the current must go back through the battery.

• Therefore because it takes some energy to more the current even a battery has resistance.

Internal Resistance:

Internal Resistance: • E = I (R + r) IB Notation:

• E = EMF• I = Current in the system• R = Resistance in system• r = Resistance in the battery

Internal Resistance:

• http://www.youtube.com/watch?v=IftDnfr5ow0

Unit Analysis for Tesla:• A particle carrying a charge of 1 coulomb and passing through a magnetic

field of 1 tesla at a speed of 1 meter per second perpendicular to said field experiences a force with magnitude 1 newton, according to the Lorentz force law. As an SI derived unit, the tesla can also be expressed as

• Units used:– A = ampere– C = coulomb– kg = kilogram– m = meter– N = newton– s = second– T = tesla– V = volt– Wb = weber

Faraday / Lenz’s Law:• Brightstorm: Faraday Lenz’s Law

– http://www.youtube.com/watch?v=qWu82nJS42I