Q: A neon atom has 56 neutrons, 78 protons, and 75 electrons. What is the net charge in Coulombs on the atom?

$$4.8 \times 10$$^{-19}$$ \times 3 C$$

Question 1

A neon atom has 56 neutrons, 78 protons, and 75 electrons. What is the net charge in Coulombs on the atom?

Accepted Answer

$$4.8 	imes 10$$^{-19}$$ 	imes 3 C$$

Question 2

Two charges Q1 and Q2 are placed at the vertices of an equilateral triangle. If Q1 is $$+2 \mu C$$ and Q2 is $$-2 \mu C$$, what is the direction of the net electric field at the third vertex?

Accepted Answer

Perpendicular to the base of the triangle

Question 3

A charge is distributed uniformly along a long straight line segment. If the linear charge density is $$\lambda = 2 \mu C/m$$, what is the electric field at a point 1 m away from the line?

Accepted Answer

$$E = \frac{\lambda}{2 \pi \$$epsilon_0$$ r}$$

Question 4

An electroscope is positively charged by touching it with a glass rod rubbed with silk. The electroscope leaves spread apart after the rod is removed. There is a charged metal plate framed closely to the electroscope without touching it. What happens to the leaves?

Accepted Answer

The leaves spread further apart.

Question 5

A $$+2 \mu C$$ charge is fixed at point A $$(0,0)$$ and a $$-2 \mu C$$ charge is fixed at point B $$(0,2) on $$the y-axis. What is the magnitude of the electric field at the origin?

Accepted Answer

$$1.8 	imes 10^5$ N/C

Question 6

A thin conducting sheet with uniform positive charge is placed in the xy-plane. What is the direction of the electric field just above the sheet?

Accepted Answer

Perpendicular to the sheet, pointing away

Question 7

Consider two charges positioned as shown: $$Q_1 at$$ $$(0,0)$$ and $$Q_2 at$$ $$(a,0). In $$which region(s) is the net electric field zero?

Accepted Answer

At a point between $$Q_1$$ and $$Q_2$$

Question 8

A $$+4 \mu C$$ charge is placed at $$(0,0)$$ and a $$-2 \mu C$$ charge is placed at $$(0,2) on $$the y-axis. What is the direction of the net electric field at $$(0,1)$$?

Accepted Answer

Downward along the y-axis

Question 9

The figure shows the E-field at three points near two charges, Q1 and Q2. If the field at point P is directed to the right, what can you conclude about the relative magnitudes of Q1 and Q2?

Accepted Answer

Q2 is larger than Q1

Question 10

A charge $$Q is $$placed at the origin. What is the electric field at a point $$(x,0) on $$the x-axis?

Accepted Answer

$$E = \frac{Q}{4 \pi \$$epsilon_0$$ x^2$}$$

Question 11

A $$+3 \mu C$$ charge is placed at $$(0,0)$$ and a $$-3 \mu C$$ charge is placed at $$(0,2) on $$the y-axis. What is the potential difference between $$(0,1)$$ and $$(0,2)$$?

Accepted Answer

$$V = \frac{1}{4 \pi \$$epsilon_0$$} \left( \frac{3}{1} - \frac{3}{2} \right)$$

Question 12

A charged particle moves in a uniform electric field. Which of the following statements is true?

Accepted Answer

The particle accelerates in the direction of the field if positive

Question 13

A thin sheet of metal is placed in a uniform electric field. What happens to the field inside the metal?

Accepted Answer

It is zero

Question 14

A $$+2 \mu C$$ charge is placed at $$(0,0)$$ and a $$-2 \mu C$$ charge is placed at $$(0,2) on $$the y-axis. What is the direction of the force on a $$+1 \mu C$$ test charge placed at $$(0,1)$$?

Accepted Answer

Downward along the y-axis

Question 15

A conducting sphere is placed in a uniform electric field. What is the net force on the sphere?

Accepted Answer

Zero

Question 16

A $$+2 \mu C$$ charge is placed at $$(0,0)$$ and a $$-2 \mu C$$ charge is placed at $$(0,2) on $$the y-axis. What is the potential at $$(0,1)$$?

Accepted Answer

$$V = \frac{1}{4 \pi \$$epsilon_0$$} \left( \frac{2}{1} - \frac{2}{1} \right)$$

Question 17

A $$+2 \mu C$$ charge is placed at $$(0,0)$$ and a $$-2 \mu C$$ charge is placed at $$(0,2) on $$the y-axis. What is the work required to move a $$+1 \mu C$$ test charge from $$(0,1) to$$ $$(0,2)$$?

Accepted Answer

$$W = q(V_2$ - V_1$)$$

Electric Charges, Forces, and Electric Fields: Example Quiz Study Notes

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