5.70. Ohm’s Law http://www.ck12.org
MEDIA
Click image to the left for use the URL below.
URL: http://www.ck12.org/flx/render/embeddedobject/5058Using Ohm’s Law to Calculate Current
You can use the equation for current (above) to calculate the amount of current flowing through a circuit when the
voltage and resistance are known. Consider an electric wire that is connected to a 12-volt battery. If the wire has a
resistance of 2 ohms, how much current is flowing through the wire?
Current =12 volts2 ohms= 6 ampsQ:If a 120-volt voltage source is connected to a wire with 10 ohms of resistance, how much current is flowing
through the wire?
A:Substitute these values into the equation for current:
Current =120 volts20 ohms= 12 ampsSummary
- According to Ohm’s law, greater voltage results in more current and greater resistance results in less current.
- Ohm’s law can be represented by the equation:’
Current(amps) =ResistanceVoltage(volts(ohms))
- This equation can be used to calculate current when voltage and resistance are known.
Vocabulary
- Ohm’s law: Law stating that current increases as voltage increases or resistance decreases.
Explore More
Review Ohm’s law and how to calculate current at the following URL. Then try to solve the two problems at the
bottom of the Web page. Be sure to check your answers against the correct solutions. http://www.grc.nasa.gov/
WWW/k-12/Sample_Projects/Ohms_Law/ohmslaw.html
Review
- State Ohm’s law.
- An electric appliance is connected by wires to a 240-volt source of voltage. If the combined resistance of the
appliance and wires is 12 ohms, how much current is flowing through the circuit?