2. • Voltage – an electromotive force or potential difference expressed in volts.
It provides the “push” in order for the current to flow in a conducting
material.
- the larger the voltage is, the higher the current in that material.
• Resistance – impedes the current, electrons will flow slower when the
resistance of the material is high.
3. OHM’S LAW
• developed by a German physicist Georg Simon Ohm (1789-1854), who
described measurements of applied voltage and current through simple
circuits containing various lengths of wire in 1827.
• describes the relationship between current I, voltage V, and resistance R.
• Materials that obey Ohm’s law are called ohmic materials.
• Formulas:
4. Given: voltage = 12 V; current = 3.0 A; resistance = ?
Solution:
R =
𝑽
𝑰
R =
𝟏𝟐 𝑽
𝟑.𝟎 𝑨
= 4 Ω
Answer:
The resistance of the headlights is 4 Ω.
S
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p
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#
1
The headlights of a typical car are powers by a 12-V battery.
What is the resistance of the headlights if they draw 3.0 A of
current when turned on?
5. Given: voltage = 45.0 V; resistance = 30.0 Ω; current = ?
Solution:
I =
𝑽
𝑅
I =
45.0 𝑽
30.0Ω
= 1.5 A
Answer:
The current on the wire is 1.5 A.
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1
What is the current through a wire that has a resistance of 30.0
Ω if the voltage across is 45.0 V?
