Q: What is the magnitude of the elementary charge?

$$1.602 \times 10$$^{-19}$$\ \mathrm{C}$$

Question 1

Which of the following statements best describes the law of conservation of electric charge?

Accepted Answer

Electric charge is always observed as integer multiples of the elementary charge and cannot be created or destroyed, only transferred.

Question 2

A glass rod is rubbed with silk and becomes positively charged. What happens to the silk?

Accepted Answer

The silk becomes negatively charged.

Question 3

What is the magnitude of the elementary charge?

Accepted Answer

$$1.602 	imes 10$$^{-19}$$\ \mathrm{C}$$

Question 4

Which of the following best explains why a neutral object can be charged by frictional contact?

Accepted Answer

Friction transfers existing charges between objects.

Question 5

A conductor is connected to the ground and then brought near a charged object. What happens to the conductor?

Accepted Answer

It becomes polarized and may gain or lose charge depending on the situation.

Question 6

Which of the following is true about electric field lines?

Accepted Answer

Electric field lines begin on positive charges and end on negative charges or at infinity.

Question 7

Two point charges, $$Q_1 = +2.0$$\ \mu\mathrm{C}$$ and Q_2$ = -1.0\ \mu\mathrm{C}$$, are placed 0.5 m apart. What is the direction of the force on $$Q_1$$ due to $$Q_2$$?

Accepted Answer

Toward $$Q_2$$

Question 8

Which equation gives the magnitude of the electric force between two point charges $$q_1$$ and $$q_2$$ separated by distance $$r$$?

Accepted Answer

$$F = k_e \frac{|q_1$ q_2$|}{r^2$}$$

Question 9

A neutral water molecule is placed near a charged rod. What happens to the water molecule?

Accepted Answer

It becomes polarized, aligning its dipole with the electric field.

Question 10

Which of the following best describes the direction of the electric field at a point near a positive point charge?

Accepted Answer

Radially outward away from the charge

Question 11

A test charge $$q is $$placed in an electric field $$\vec{E}. $$What is the force experienced by the test charge?

Accepted Answer

$$\vec{F} = q \vec{E}$$

Question 12

Which of the following is a property of conductors in electrostatic equilibrium?

Accepted Answer

The electric field inside the conductor is zero.

Question 13

If three point charges are placed at the vertices of an equilateral triangle, how do you find the net force on one of the charges?

Accepted Answer

By vector addition of the forces due to the other two charges.

Question 14

Which of the following statements about electric field lines is correct?

Accepted Answer

The density of electric field lines indicates the strength of the electric field.

Question 15

A charged particle is placed at rest in a uniform electric field. What will happen to the particle?

Accepted Answer

It will move parallel to the field if positively charged, and antiparallel if negatively charged.

Question 16

Which of the following best describes a dipole?

Accepted Answer

A configuration of two opposite charges separated by a distance.

Question 17

If the spacing between electric field lines increases, what happens to the magnitude of the electric field?

Accepted Answer

The magnitude of the electric field decreases.

Question 18

Which of the following is true about the force between two like charges?

Accepted Answer

They repel each other.

Question 19

A charged sphere is disconnected from the ground after being polarized by a nearby charged rod. What is the net result?

Accepted Answer

The sphere retains a net charge.

Question 20

Which of the following is the correct vector form of Coulomb's Law for the force between two point charges $$q_1$$ and $$q_2$$ separated by a distance $$r$$?

Accepted Answer

$$\vec{F} = k_e \frac{q_1$ q_2$}{r^2$} \hat{r}$$

Electric Charge and Electric Fields – Physics for Life Sciences II (Lecture 6)

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