Transcript 10.3 Charges at Work: (Pages 418-427) Homework: Page 428 # 3, 4, 7, 8 Key Concepts: (Page 428)

10.3 Charges at Work:
(Pages 418-427)
Homework: Page 428 # 3, 4, 7, 8
Key Concepts: (Page 428)
• A lightning rod is a metal
sphere or point that is
attached to the highest part
of a building and connected
to the ground.
• A lightning rod reduces the
likelihood of a lightning strike.
If there is a lightning strike,
the lightning is more likely to
strike the lightning rod than
the building it protects, and
then to be conducted to the
ground.
• Lightening Rods
• An electrostatic precipitator removes
unwanted dust particles and liquid droplets
from a flow of gas.
• An electrostatic separator uses induced charges
to separate particles that have different masses.
• A Van de Graaff generator is capable of
generating very large charges.
• In the dark, selenium is only
a fair conductor. When
exposed to light, it becomes
a very good conductor.
Selenium-coated drums are
used in photocopiers, laser
printers, and scanners.
• Watch This
• A radiation dosimeter is a
small device that detects
and measures exposure to
radiation.
Lightning:
1. Visualizing Lightning. Draw figure 10.17
on page 419
2. Explain how a lightning rod
works.
• A lightning rod is a metal sphere or point
that is attached to the highest part of a
building and connected to the ground.
• A thick, insulated copper wire connects the
lightning rod to a metal plate or bare metal
cable in the ground.
• Since the cable is bare, it allows the
charges to be conducted into the ground.
3. Why does lightning tend to strike
the tallest building nearby?
• Lightning takes the path of least resistance
between a cloud and the ground, usually
striking the highest object in an area.
4. What are some of the hazards of
a lightning strike?
• Since the lightning strike has a very large
electric current, it can lead to hazards
such as forest fires and deaths.
5. Why does lightning follow a
jagged path?
• Lightning follows a jagged path because
air currents and turbulence produce
regions of differing conductivity for the
lightning discharge to follow.
6. List & explain different uses of
electrostatics.
Electrostatic Precipitator
• A type of cleaner that removes unwanted
particles and liquid droplets from a flow of gas
• Dust and pollen particles are charged, and then
attracted to an oppositely charged or grounded
plate
• When the particles collide with the collection
plate, they are neutralized, collected, and
removed
6. List & explain different uses of
electrostatics.
Electrostatic Spray Painting
• The paint or powder is given a charge as it
leaves the nozzle of the sprayer
• The object to be coated is either grounded
or given a charge that is opposite to the
charge of the particles in the spray
• Thus, the particles are attracted to the
object being coated, minimizing the
amount of over-spray
7. What is a Van de Graaf
generator?
• It is a device that can accumulate or
transfer very large charges
8. What function does a Van de
Graaf generator play in an atom
smasher?
• The Van de Graaf generator can
accelerate particles to very high speeds
9. Why is it important to have a radiation
dosimeter if a person works in a facility that has
equipment that emits radiation?
• Since a radiation dosimeter detects and
measures exposure to radiation, it would
be important to have one in this type of
facility in order to determine
dangerous/hazardous levels of radiation.