Question

1. At the level of the atom, both electric force and gravitational force can be evaluated for the interaction between protons and electrons. Which is dominant?

a. The gravitational force
b. The electric force
c. Both forces are approximately equal
d. Neither force is very strong at the atomic level
e. Two of the above are correct

2. A student rubs a balloon in her hair then holds the balloon against a wall and finally releases it after a moment. Which of the following is probably not going to occur?

a. The balloon will be repelled from the wall
b. The balloon will slowly slide down the wall
c. The balloon will remain in place without moving
d. All of they above
e. Two of the above are correct

3. Which of the following is scientifically verified evidence that the smallest unit of charge for an isolated particle is the same as the charge found on an electron?

a. Electrons and protons are always found in equal numbers for all systems.
b. Protons have the same magnitude of charge as electrons.
c. Charge is quantized.
d. Quarks have the same magnitude of charge as an electron.

4. During a storm, the base of a cloud acquires a large negative charge. Which, of the following is a likely result?

a. The top of a tall tree will also become negatively charged.
b. The top of a tall tree will become positively charged.
c. Electrons from the ground will attempt to move toward the cloud by way of lightning.
d. Electrons at the top of a top tree will move toward the ground.
e. Two of the above are correct.

Answer 1

1)

The electrostatic constant is about 10²⁰ times larger than the gravitational constant. That's why electrostatic force is largely dominant for the subatomic particles.
Correct answer is B.

2)

Due to induction the wall will be oppositely charged and the balloon will stick to it firstly and then slowly radiate charge as the wall is connected to the ground and fall off after a short time. But there is really no chance of the balloon to be repelled by the wall, because induction doesn't create the same type of charges in two objects, and same charges repel each other. So there is no chance of repelling.

Option A is correct

3)

The amount of charge in an object is always a multiplier of a certain amount of charge. This is called the quantization of charge. And electrons happen to carry this charge which is equal to a proton's charge. As everything is made of electrons and protons then we can say that the smallest unit of charge for an isolated particle is the same as the charge found on an electron.

Option B is correct.

4)

Same as the balloon situation anything on the ground near the cloud will have induced positive charge. Positive charge is a deficiency of electrons, electrons move away to make a spot positively charged(in this case the cloud's electrons repel them from the top of the tree) and negative charge means an excess of electrons. As electrons move towards the positive potential, so charge from the clouds tries to move towards the ground. As option b and d is relevant, so,

Option E is correct.