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A scientist is researching what happens when a neutral metal sphere located on an insulated stand is touched by a negatively charged rod.

The set up for the scientist's experiment is shown in the picture below.
What will happen to the excess electrons when the negatively charged rod touches the metal sphere?
(1 point)
• The excess electrons will move from the rod to the sphere and stay
close together.
The excess electrons will move from the sphere to the rod and stay close together.
The excess electrons will move from the rod to the sphere and spread out.
The excess electrons will move from the sphere to the rod and spread out.

9 answers

When the negatively charged rod touches the neutral metal sphere, the excess electrons from the rod will move to the sphere. Since the sphere is a conductor, these excess electrons will then spread out across the surface of the sphere. Therefore, the correct answer is:

The excess electrons will move from the rod to the sphere and spread out.

Isabella is researching how to charge objects through friction. Isabella rubs a balloon on her hair. When she pulls the balloon away from her hair, the hair is attracted to the balloon. Which BEST explains why the hair becomes attracted to the balloon? (1 point)
Rubbing the balloon along her hair creates electrons that will stick to both the balloon and her hair.
Rubbing the balloon along her hair creates protons that will stick to both the balloon and her hair.
Rubbing the balloon along her hair moves protons from the balloon to her hair.
Rubbing the balloon along her hair moves electrons from her hair to the balloon.

The best explanation for why the hair becomes attracted to the balloon after rubbing is that rubbing the balloon along her hair moves electrons from her hair to the balloon. This leaves the hair positively charged and the balloon negatively charged, resulting in the attraction between the two.

Therefore, the correct answer is:

Rubbing the balloon along her hair moves electrons from her hair to the balloon.

You are holding two negatively charged balloons. What will happen if you bring the balloons close to each other? (1 point)
• The amount of the electrostatic force between the balloons will increase, and they will attract each other.
The amount of the electrostatic force between the balloons will decrease, and they will repel each other.
The amount of the electrostatic force between the balloons will increase, and they will repel each other.
The amount of the electrostatic force between the balloons will decrease, and they will attract each other.

When you bring two negatively charged balloons close to each other, they will repel each other due to the like charges. As they get closer, the amount of the electrostatic force between them will actually increase.

Therefore, the correct answer is:

The amount of the electrostatic force between the balloons will increase, and they will repel each other.

As you are sliding down a plastic slide in a playground, your hair stands up on its ends. Which statement best explains why your hair stands up after sliding down the plastic slide? (1 point)
Energy is transferred from you to the slide through conduction, causing your hair to become charged and stand up.
Friction causes a transfer of electrons between the slide and you, making your like-charged hairs attract the air through induction.
Friction causes a transfer of electrons between the slide and you, making each of your like-charged hairs repel each other.
Energy is transferred from the slide to you through induction, causing
• your hair to become charged and stand up.

The best explanation for why your hair stands up after sliding down the plastic slide is that friction causes a transfer of electrons between the slide and you. As you slide down the plastic slide, electrons transfer from the slide to your body, giving you a negative charge. Since like charges repel, the negatively charged hairs on your head repel each other, causing them to stand up.

Therefore, the correct answer is:

Friction causes a transfer of electrons between the slide and you, making each of your like-charged hairs repel each other.

Which statement about electric insulators is true? (1 point)
• Charges within electric insulators do not readily move.
• Electric charges move freely in electric insulators.
• Electric insulators are the best heat conductors.
• Electric insulators have a high flow of heat and electricity.

The true statement about electric insulators is:

Charges within electric insulators do not readily move.

This accurately describes the characteristic of electric insulators, which do not allow charges to flow freely, contrasting with conductors.