Download Electric Circuits Basics activity

Electricity Part 1
(work through this page using the links provided and submit through Moodle)
Part 1. To investigate Ohm's Law V= I R (V-battery Voltage in Volts, R-electrical Resistance in
Ohms, I-electrical current in amps)
Start with V = I R, divide both sides of this equation by R to get a new equation for I in terms of
V and R.
Write New Equation here: ( note: if you want to write a divided by b do it as a/b)
______________________________
V-battery Voltage in Volts
R-electrical Resistance in Ohms
I-electrical current in amps
Click on the link at right to open ohm's law simulator.
Ohm’sLaw
1. What happens to I when V increases? _______________
What happens to I when V decreases?_______________
What happens to I as V doubles?________________
What happens to I as V halves?________________
What happens to I as V triples?________________
What happens to I as V drops to one-third?________________
2. What happens to I when R increases? _______________
What happens to I when R decreases?_______________
What happens to I as R doubles?________________
What happens to I as R halves?________________
What happens to I as R triples?________________
What happens to I as R drops to one-third?________________
3. For a battery voltage of 6.0 V what current will you get with a 100 Ohm resistor? (mA means
milliamp……..1000 mA = 1 A)
I= __________________
4. For a battery voltage of 6.0 V what resistor is needed to limit the current to 10 mA (0.010 A)
?
R= __________________
5. What battery voltage is needed to cause 30 mA (0.030A) to flow through a 100 Ohm resitor?
V=_________________________
Part 2. To investigate Electrical Resistance R of a wire.
R: Resistance in Ohms
: resistivity of the wire's material in Ohms-cm
(Glass is large copper is small)
L: wire length
A: cross sectional area of the wire.
Click on the link at right to open Resistance Simulator.
In your own words explain how the resistance of a wire changes with , L, and A.
Two Tungsten light bulb filaments of identical lengths are connected to a household circuit of
120 V. Filament A is thicker than Filament B.
Which filament has the largest electrical resistance? A or B
answer
When connected to 120 V, which filament has the largest electrical current? A or B answer
Which filament will glow brightest in your home? (remember Power= I V) A or B answer
If one is rated 40 Watts and the other 100 Watts, which one is the 40 Watt bulb? answer
(see next page for selected answers)
When connected to 120 V, which filament has the largest electrical current? A or B answer
B is thinner so it has more resistance than A. smaller resistance means more current.
Which filament will glow brightest in your home? (remember Power= I V) A or B answer
Bulb A glows brighter since it has more current in it when connected to the 120 V household
electrical voltage source.