review and assessment
lesson 1 electric charge and static electricity
1. what type of charge transfer occurs when two objects are rubbed together?
a. friction b. induction
c. conduction d. polarization
2. the transfer of electrons from a cloud to the ground during a lightning strike is an example of ______
3. apply concepts draw the electric field for a single positive charge. be sure to show which way the field lines point.
4. relate cause and effect explain what happens to the electrons in a metal object when it is held near a negatively charged object. what happens to the overall charge of the metal object?
5. write about it a park needs a sign to tell visitors what to do during a thunderstorm. write a paragraph that explains why standing under a tall tree during a thunderstorm is dangerous.
lesson 2 electric current
6. which of these objects is an insulator?
a. gold ring b. copper coin
c. glass rod d. steel fork
7. an electric current is ______
8. classify the appliances in your home can be made of several different materials. what kinds of materials are the wires made of? what kinds of materials surround the wire for safety?
image of a toaster
9. infer copper wires carry electric current from power plants to users. how is the resistance of these power lines likely to vary during the year in an area that has very hot summers? explain.
10. make models water will not flow down a flat slide because there is no potential energy difference between the two ends. how could this situation be represented in an electric circuit? explain your reasoning.

Question

review and assessment
lesson 1 electric charge and static electricity
1. what type of charge transfer occurs when two objects are rubbed together?
   a. friction  b. induction
   c. conduction  d. polarization
2. the transfer of electrons from a cloud to the ground during a lightning strike is an example of ______
3. apply concepts draw the electric field for a single positive charge. be sure to show which way the field lines point.
4. relate cause and effect explain what happens to the electrons in a metal object when it is held near a negatively charged object. what happens to the overall charge of the metal object?
5. write about it a park needs a sign to tell visitors what to do during a thunderstorm. write a paragraph that explains why standing under a tall tree during a thunderstorm is dangerous.
lesson 2 electric current
6. which of these objects is an insulator?
   a. gold ring  b. copper coin
   c. glass rod  d. steel fork
7. an electric current is ______
8. classify the appliances in your home can be made of several different materials. what kinds of materials are the wires made of? what kinds of materials surround the wire for safety?
image of a toaster
9. infer copper wires carry electric current from power plants to users. how is the resistance of these power lines likely to vary during the year in an area that has very hot summers? explain.
10. make models water will not flow down a flat slide because there is no potential energy difference between the two ends. how could this situation be represented in an electric circuit? explain your reasoning.

Accepted Answer

### Question 1:
# Explanation:
## Step1: Recall charge transfer methods
Friction: charge transfer by rubbing. Induction: without contact. Conduction: direct contact. Polarization: charge separation.
## Step2: Match with rubbing objects
When two objects are rubbed, it's friction. So option a is correct.
# Answer: a. friction

### Question 6:
# Explanation:
## Step1: Recall insulator definition
Insulators don't conduct electricity. Metals (gold, copper, steel) are conductors. Glass is an insulator.
## Step2: Identify insulator object
Among options, glass rod (c) is insulator. Gold ring (a), copper coin (b), steel fork (d) are conductors.
# Answer: c. glass rod

### Question 7:
# Explanation:
## Step1: Recall electric current definition
Electric current is the flow of electric charge (usually electrons) through a conductor.
## Step2: Formulate the answer
An electric current is the flow of electric charge (usually electrons) in a circuit or conductor.
# Answer: the flow of electric charge (usually electrons)

### Question 8:
# Explanation:
## Step1: Recall wire and insulation materials
Wires in home appliances: made of conductors (like copper, aluminum) to carry current. Insulation: made of insulators (like rubber, plastic) for safety (prevent electric shock).
## Step2: Explain the materials
Wires: conductors (e.g., copper) to allow current flow. Surrounding: insulators (e.g., rubber/plastic) to prevent contact with current, ensuring safety.
# Answer: Wires: conductors (e.g., copper); Surrounding: insulators (e.g., rubber/plastic)

### Question 9:
# Explanation:
## Step1: Recall resistance and temperature relation
Resistance of a conductor (like copper) increases with temperature (since atoms vibrate more, impeding electron flow).
## Step2: Apply to hot summers
In hot summers, power lines (copper) heat up. So their resistance increases (as temperature rises, resistance of copper increases).
# Answer: Resistance increases. Copper’s resistance rises with temperature; hot summers heat lines, increasing resistance.

### Question 10:
# Explanation:
## Step1: Relate water flow to electric circuit
Water flows with potential energy difference (height difference). In electric circuit, current flows with voltage (potential difference) between two points.
## Step2: Model the situation
A flat slide (no height difference) is like a circuit with no voltage (potential) difference between two points (e.g., same node, or battery shorted? No, better: a circuit with two points at same voltage, so no current. Like a wire connecting two ends of a battery with same voltage—no current. So represent as a circuit with no potential difference (e.g., two points at same voltage, so no current flows), like a wire between two identical voltage sources or a circuit with zero voltage across a component.
# Answer: Represent as a circuit with no potential (voltage) difference between two points (e.g., a wire connecting two ends of a battery with same voltage, so no current flows). Just as water needs height difference, current needs voltage difference; no voltage difference means no current (like no water flow on flat slide).

### Question 4:
# Explanation:
## Step1: Recall charge interaction (induction)
Negatively charged object repels electrons in metal (since electrons are negative).
## Step2: Describe electron and charge change
Electrons in metal move away from the negative object (to the far side of the metal). The metal’s overall charge: remains neutral (no charge added/removed), but charge is polarized (near side positive, far side negative).
# Answer: Electrons move away (repelled by negative object). Overall charge: neutral (charge polarized, not added/removed).

### Question 5:
# Explanation:
## Step1: Recall lightning and tree physics
Tall trees are conductors (moist, tall—attract lightning). Standing under: lightning can strike tree, current can jump to you (since you’re close, and ground current spreads from tree, or you’re in electric field).
## Step2: Write the paragraph
During a thunderstorm, standing under a tall tree is dangerous. Trees are tall, conductive (moist), so they attract lightning. If lightning strikes the tree, the large current can travel through the tree to the ground. You, standing nearby, can be hit by the lightning’s current (through air, or via ground current spreading from the tree’s base). Also, the tree’s charge induction can put you at risk. Seek low, open areas (not under trees) and stay away from tall objects.
# Answer: [Paragraph] During a thunderstorm, standing under a tall tree is dangerous. Trees are tall and often conductive (due to moisture), making them prime targets for lightning. If lightning strikes the tree, the massive electric current will travel down the tree to the ground. A person under the tree is at risk of being struck by the lightning’s current (either directly from the tree to the person or via the ground current spreading from the tree’s base). Additionally, the tree’s electric field can induce charges in nearby objects, increasing the danger. To stay safe, seek a low - lying, open area (away from tall objects like trees) and avoid contact with conductive materials.

Sovi.AI - AI Math Tutor

QUESTION IMAGE

Question

Explanation:

Question 1:

Step1: Recall charge transfer methods

Step2: Match with rubbing objects

Step1: Recall insulator definition

Step2: Identify insulator object

Step1: Recall electric current definition

Step2: Formulate the answer

Answer:

Question 6: