Q: What is the value of the proportionality constant $$k in $$Coulomb's Law?

$$k = 8.988 \times 10^9$ \text{ N} \cdot \text{m}^2/\text{C}^2$$

Question 1

Which statement best describes the law of conservation of electric charge?

Accepted Answer

The total electric charge in an isolated system remains constant during any interaction.

Question 2

A neutral atom becomes positively charged when:

Accepted Answer

It loses electrons.

Question 3

Which of the following materials is most likely to be a conductor?

Accepted Answer

Copper

Question 4

When a charged rod is brought near a neutral metal object, the metal object can become charged by:

Accepted Answer

Conduction or induction

Question 5

Which equation correctly expresses Coulomb's Law for the magnitude of the force between two point charges?

Accepted Answer

$$F = k \frac{Q_1$ Q_2$}{r^2$}$$

Question 6

A charged electroscope is used to determine the sign of an unknown charge. What will happen if a positively charged object is brought near a positively charged electroscope?

Accepted Answer

The leaves will spread further apart.

Question 7

What is the value of the proportionality constant $$k in $$Coulomb's Law?

Accepted Answer

$$k = 8.988 	imes 10^9$ 	ext{ N} \cdot 	ext{m}^2/	ext{C}^2$$

Question 8

Which of the following best describes the electric field inside a conductor in electrostatic equilibrium?

Accepted Answer

It is zero.

Question 9

The electric field at a distance $$r$$ from a point charge $$Q is $$given by:

Accepted Answer

$$E = k \frac{Q}{r^2$}$$

Question 10

Which statement about electric field lines is correct?

Accepted Answer

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

Question 11

A DNA molecule's double helix structure is stabilized by:

Accepted Answer

Electrostatic forces between A-T and G-C base pairs.

Question 12

In a photocopy machine, why do toner particles stick to certain areas of the drum?

Accepted Answer

Because those areas are positively charged and attract the negatively charged toner.

Question 13

Which formula represents the electric flux $$\Phi_E$$ through a surface at an angle $$	heta to $$the field?

Accepted Answer

$$\Phi_E = EA \cos 	heta$$

Question 14

Gauss's Law relates the net electric flux through a closed surface to:

Accepted Answer

The total charge enclosed by the surface.

Question 15

A parallel plate capacitor has plates with charges $$+Q$$ and $$-Q. $$What is true about the electric field between the plates?

Accepted Answer

It is constant and directed from the positive to the negative plate.

Question 16

If three point charges are placed at the vertices of an equilateral triangle, what is the net force on one charge due to the other two?

Accepted Answer

The net force is the vector sum of the two forces.

Question 17

Which of the following is the correct expression for the force on a charge $$q in an $$electric field $$\vec{E}$$?

Accepted Answer

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

Question 18

Which property distinguishes a polar molecule from a nonpolar molecule?

Accepted Answer

A polar molecule has an uneven distribution of charge.

Question 19

What is the charge of a single electron?

Accepted Answer

$$e = 1.602 	imes 10$$^{-19}$$ 	ext{ C}$$

Question 20

Which of the following statements about the superposition principle is correct?

Accepted Answer

The net electric field at a point is the vector sum of the fields from each charge.

Electric Charge and Electric Field: Principles and Applications (Chapter 16 Study Notes)

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