1 / 13

Ohm’s Law –Pg 681

Ohm’s Law –Pg 681. Electric Current, Voltage and Resistance. Electric Current. N. Is the flow of charge. In solid conductors, electrons carry the charge through the circuit. Electric current is measured in AMPERES (A). Net charge of a wire. N. The net charge of a wire is ZERO.

angela-gillespie
Download Presentation

Ohm’s Law –Pg 681

An Image/Link below is provided (as is) to download presentation Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author. Content is provided to you AS IS for your information and personal use only. Download presentation by click this link. While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server. During download, if you can't get a presentation, the file might be deleted by the publisher.

E N D

Presentation Transcript

  1. Ohm’s Law –Pg 681 Electric Current, Voltage and Resistance

  2. Electric Current N • Is the flow of charge. • In solid conductors, electrons carry the charge through the circuit. • Electric current is measured in AMPERES (A).

  3. Net charge of a wire N • The net charge of a wire is ZERO. • Number of electrons in the wire equal the number of protons in the atomic nuclei.

  4. Voltage Sources N • Something that provides a potential difference is called a voltage source. • Ex: Batteries n generators. • Provides an “electric pressure” for the electrons to move between the terminals. • In U.S, plugs have a “pressure” of 120 V.

  5. Electric Resistance N • Current depends on the resistance the conductor offers to the flow of charge – Electric Resistance. • Resistance depends on the conductivity of the material (how well it conducts), its thickness and its length. • Thick wires have less resistance and longer wires have more resistance. • Electric resistance is measured in OHMS (Ω).

  6. Ohm’s Law N • Gives the relationship between voltage, current and resistance. • States that • The current in a circuit is directly proportionate to the voltage across the circuit and inversely proportionate to the resistance of the circuit. • Current (I)= Voltage (V) • Resistance (R) I = V/R

  7. Current in a circuit N • 1. If the voltage is doubled, while the resistance is the same, the current _________. • 2. If the voltage is the same, while the resistance is doubled, the current _________. • So to decrease current, we have to ______ resistance.

  8. Problems on Ohm’s Law N N • Calculate the current in a toaster that has a heating element of 14 ohms when connected to a 120-V outlet. • Given: V= 120V; R = 14 Ohms • U: I=? Eq: I = V/R • Subst: I = 120/14 = 8.6 A

  9. Problems on Ohm’s Law N • How much current moves through your fingers of resistance 1200Ω, if you touch them to the terminals of a 6V battery? • Given: R= 1200Ω; V= 6V • Unknown: I=? Eq: I = V/R • Subst: I = 6/1200 • = 0.005 A

  10. Causes of Electric Shock N More current flows through you if your body has less resistance. Your body has less resistance if you are wet, so you are more likely to get a severe shock.

  11. High-Voltage Wires N • Birds do not receive a shock as they are at the same potential as the wire. • If they touch the ground (or another wire) while touching the wire, they will get a shock.

  12. Rescuing shock victims • First clear them of the electric power supply wires with a wooden stick (any non conductor) so that you don’t get electrocuted yourself !!!

  13. Do Now • Turn to Pg 696 and answer Q 5, 10, 11, 12, 13, 14, 15, 16, 17, 34, 35

More Related