1 Electric Fields Learning Outcomes Describe electric fields
1 Electric Fields – Learning Outcomes Describe electric fields. Note the vector nature of electric fields. Demonstrate an electric field pattern. HL: Define electric field strength. HL: Solve problems about electric field strength. Describe precipitators. Describe xerography (photocopying). Discuss the hazards of electric fields on integrated circuits.
2 Describe Electric Fields Electric fields are the region of space in which electric forces are felt. Electric fields are represented with electric field lines. The lines connect charges. Lines have arrows that show the direction of the force on a positive charge. Lines that are closer together indicate a stronger field. e. g. Draw the electric field around a negative charge.
3 Describe Electric Fields Some more complicated fields: Draw the field around two negative charges.
4 Describe Electric Fields Some more complicated fields:
5 Describe Electric Fields Some more complicated fields:
6 Demonstrate an Electric Field Pattern 1. Part fill a petri dish with cooking oil. 2. Immerse two metal plates at opposite ends of the petri dish. 3. Connect each plate to a terminal of a high voltage power supply. 4. Sprinkle ground rice over the oil. 5. The ground rice lines up in the shape of the electric field between the plates.
7 Demonstrate an Electric Field Pattern
8 HL: Define Electric Field Strength
9 HL: Solve Problems
10 HL: Solve Problems Draw the direction of the electric field at P. Calculate the electric field strength at P.
11 HL: Solve Problems
12 Describe Precipitators are used to remove dust and other small particles from air. The ‘dirty’ gas passes through a negatively charged grid which transfers this charge to the dust. Later, the gas passes between positively charged plates. The negative dust sticks to the plates and the air is cleaned.
13 Describe Xerography Light shines on paper, which reflects where it is white and absorbs where it is black. The reflected light hits a charged drum and discharges it in those areas it hits. The remaining charge acts like a photo negative.
14 Describe Xerography The drum rotates through negatively charged toner which sticks to the positively charged parts of the drum. The drum rolls over positively charged paper, which takes the toner. The paper passes through heated rollers, binding the toner to the paper.
15 Describe Xerography
Discuss Hazards on Integrated Circuits Static charges will damage integrated circuits (e. g. computer chips, motherboards) if discharged nearby. People who work with these devices often use anti-static bracelets which connect them to ground. by Kms – CC-BY-SA-3. 0 16
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