Q: A positive test charge of $$3.0 \times 10$$^{-8}$$ C experiences a force of 6.0$$ \times $$10^{-8} N. $$What is the electric field at that location?

$$E = \frac{6.0 \times 10$$^{-8}$$ \text{ N}}{3.0 \times 10$$^{-8}$$ \text{ C}} = 2.0 \text{ N/C}$$

Q: If a charge of $$+12 \times 10$$^{-8}$$ C replaces the test charge in the previous question, what force will it experience in the same electric field?

$$F = E q = 2.0 \text{ N/C} \times 12 \times 10$$^{-8}$$ \text{ C} = 24 \times 10$$^{-8}$$ \text{ N}$$

Q: What is the value of the permittivity of free space $$\$$varepsilon_0$$?

$$\$$varepsilon_0$$ = 8.85 \times 10$$^{-12}$$ \text{ C}^2/\text{N} \cdot \text{m}^2$$

Q: If the electric field at a point is $$2.0 \text{ N/C}$$, what force does a charge of $$0.18 \times 10$$^{-8}$$ C experience?

$$F = E q = 2.0 \text{ N/C} \times 0.18 \times 10$$^{-8}$$ \text{ C} = 0.36 \times 10$$^{-8}$$ \text{ N}$$

Question 1

Which equation correctly represents Coulomb's Law for the force between two point charges $$q_1$$ and $$q_2$$ separated by a distance $$r in a $$vacuum?

Accepted Answer

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

Question 2

A test charge $$q_0$$ experiences a force $$F in an $$electric field. What is the definition of the electric field $$E at $$that point?

Accepted Answer

$$E = \frac{F}{q_0$}$$

Question 3

A positive test charge of $$3.0 	imes 10$$^{-8}$$ C experiences a force of 6.0$$ 	imes $$10^{-8} N. $$What is the electric field at that location?

Accepted Answer

$$E = \frac{6.0 	imes 10$$^{-8}$$ 	ext{ N}}{3.0 	imes 10$$^{-8}$$ 	ext{ C}} = 2.0 	ext{ N/C}$$

Question 4

If a charge of $$+12 	imes 10$$^{-8}$$ C replaces the test charge in the previous question, what force will it experience in the same electric field?

Accepted Answer

$$F = E q = 2.0 	ext{ N/C} 	imes 12 	imes 10$$^{-8}$$ 	ext{ C} = 24 	imes 10$$^{-8}$$ 	ext{ N}$$

Question 5

The electric field at a point due to a point charge $$q is $$given by which equation?

Accepted Answer

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

Question 6

Two positive point charges, $$q_1 = +16$$ \mu$$C and q_2$ = +4.0 \muC$$, are separated by 3.0 m. At what distance from $$q_1 is $$the net electric field zero?

Accepted Answer

$$d = 2.0 	ext{ m}$$

Question 7

Which statement about electric field lines is correct?

Accepted Answer

Electric field lines always begin on positive charges and end on negative charges.

Question 8

The electric field between the plates of a parallel plate capacitor is given by which equation?

Accepted Answer

$$E = \frac{\sigma}{\$$varepsilon_0$$}$$

Question 9

What is the value of the permittivity of free space $$\$$varepsilon_0$$?

Accepted Answer

$$\$$varepsilon_0$$ = 8.85 	imes 10$$^{-12}$$ 	ext{ C}^2/	ext{N} \cdot 	ext{m}^2$$

Question 10

A charge is suspended at the center of a hollow, electrically neutral, spherical conductor. What charge is induced on the interior surface?

Accepted Answer

A charge of $$-q is $$induced on the interior surface.

Question 11

At equilibrium under electrostatic conditions, what is the electric field inside a conductor?

Accepted Answer

The electric field is zero at any point within a conducting material.

Question 12

Which of the following best describes the direction of the force on a positive test charge placed in an electric field?

Accepted Answer

The force points in the direction of the electric field.

Question 13

If the electric field at a point is $$2.0 	ext{ N/C}$$, what force does a charge of $$0.18 	imes 10$$^{-8}$$ C experience?

Accepted Answer

$$F = E q = 2.0 	ext{ N/C} 	imes 0.18 	imes 10$$^{-8}$$ 	ext{ C} = 0.36 	imes 10$$^{-8}$$ 	ext{ N}$$

Question 14

Which property of electric field lines indicates the strength of the electric field in a region?

Accepted Answer

The number of lines per cross-sectional area.

Question 15

What happens to the electric field just outside the surface of a conductor at equilibrium under electrostatic conditions?

Accepted Answer

The electric field is perpendicular to the surface.

Question 16

A point charge $$q = +15 \muC is in a $$vacuum. What is the electric field at a point $$0.20 m $$away?

Accepted Answer

$$E = \frac{(8.99 	imes 10^9$) 	imes 15 	imes 10$$^{-6}$$}{(0.20)^2$} = 3.37 	imes 10^6$ 	ext{ N/C}$$

Question 17

Which of the following is true about the electric field inside a hollow conductor when a charge is placed at its center?

Accepted Answer

The conductor shields the charge from external electric fields.

Question 18

In a parallel plate capacitor, what happens to the electric field as you move away from the edges and toward the center?

Accepted Answer

The electric field becomes more uniform.

Question 19

Which of the following is NOT a correct property of electric field lines?

Accepted Answer

Electric field lines can cross each other.

Lec 2

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