Electrostatics and DynamicsJeopardy

By Satvika, Tyler, Sikai, and Emily

Jeopardy Board

Electrostatics Electrostatics2A Wild

Free Response Has Appeared

Dynamics Dynamics2

100 100 100 100 100200 200 200 200 200300 300 300 300 300400 400 400 400 400500 500 500 500 500

Electrostatics 100• A conductive sphere has a charge of +4Q spread

uniformly across it. It is touched momentarily to another identical conductive sphere that has a charge of -2Q uniformly spread across its surface. How much charge is on each sphere after the two spheres touch and then separate from each other?

(A) +Q on each (B) -Q on each (C) +2Q on one sphere and 0 on the other (D) +6Q on one and 0 on the other(E) No charge on either

Electrostatics 200• The four charges have been rearranged in the same square

of side d

What is the direction of the net electric field at the center of the square?

(A) Zero field (B) → (C) ↑(D) ↓ (E) ↘

Electrostatics 300

• What is the net force on the charge Q show in the following diagram?

(A) 3kQ2/d2 (B) 6kQ2/d2 (C) 32kQ2/d2

(D) 6kQ/d2 (E) 3√(2)Q/d2

Electrostatics 400

• An electron is placed in a uniform field of E = 300 * 105 N/C. What is the magnitude of force that the electron experiences?

(A) 4.8 10-12 N(B) 5.33 10-22 N (C) 5.33 10-27 N(D) 4.8 10-17 N (E) 1.6 10-19 N

Electrostatics 500• In a uniform field between two charged plates, an electron is placed at the

labeled points A, B, and C, as shown in the following diagram:

Rank the magnitude of the force on the electron when placed at each of the three points.

(A) FA > FB > FC

(B) FC > FB> FA

(C) FA = FB = FC

(D) FB > FA = FC

(E) FA = FC > FB

Electrostatics2 100

• What is the electric field at a point halfway between two charges?

(A) kQ/a2

(B) 2kQ/a2 (C) zero (D) kQQ/a2

(E)2kQ/a2

Electrostatics2 200

• What is the electric potential halfway between the two charges?

(A) kQ/a (B) 2kQ/a(C) zero (D) 4kQ/a(E) 8kQ/a

Electrostatics2 300• A 1.0-F capacitor is connected to a 12-v power

supply until it is fully charged. The capacitor is then disconnected from the power supply, and used to power a toy car. The average drag force on the car is 2N. About how far will the car go?

(A) 36 M (B) 72 M (C) 144 M (D) 24 M (E) 12 M

Electrostatics2 400The diagram shows two parallel metal plates that are separated by

distance d. The potential difference between the plates is V. Point A is twice as far from the negative point as is point B

• Which of the following statements about the electric potential between the plates is correct?

(A) The electric potential is the same points A and B (B) The electric potential is two times larger at A than at B(C) The electric potential is two times larger at B than at A(D) The electric potential is four times larger at A than at B(E) The electric potential is four times larger at B than at A

Electrostatics2 500The diagram shows two parallel metal plates that are separated by

distance d. The potential difference between the plates is V. Point A is twice as far from the negative point as is point B

• Which of the following statements about the electric field between the plates is correct?

(A) The electric field is the same at points A and B.(B) The electric field is two times larger at A than at B (C) The electric field is two times larger at B than at A(D) The electric field is four times larger at A than at B(E) The electric field is four times larger at B than at A

Free Response 100• The specifications for three light bulbs (all follow Ohm’s

Law) are:– Light 1: Power = 12 W at 12 V– Light 2: Power = 6 W at 12 V– Light 3: Power = 3 W at 12 V

1. Draw a circuit diagram that shows the 3 bulbs in series with a 12 V battery

2. Determine the total power and operating current for this circuit

• The specifications for three light bulbs (all follow Ohm’s Law) are:– Light 1: Power = 12 W at 12 V– Light 2: Power = 6 W at 12 V– Light 3: Power = 3 W at 12 V

1. Draw a circuit diagram that shows the 3 bulbs arranged in parallel with a 12 V battery

2. Determine the total power and operating current for this circuit

Free Response 200

Two spheres, both with dielectric constant ε, are embedded one inside of the other, as illustrated below. Both have charge densities of ρ, with the larger sphere containing a positive charge and the smaller sphere containing a negative charge. Their respective radii are R and r. A charge, +q, is placed at a distance d from the center of the larger sphere.

Write the equation for the electric field felt by +q. Do not take the time to reduce this equation to its simplest terms. Both spheres are now converted to conducting material, with no other charges being made (assume the spheres are insulated from one another).

Free Response 300

Free Response 400Two spheres, both with dielectric constant ε, are embedded one inside

of the other, as illustrated below. Both have charge densities of ρ, with the larger sphere containing a positive charge and the smaller sphere containing a negative charge. Their respective radii are R and r. A charge, +q, is placed at a distance d from the center of the larger sphere.

• What is the electric force felt by charge +q? Do not take the time to reduce this equation to its simplest terms.

• An electron initially moves in a horizontal direction and has a kinetic energy of 2.0 *10^3 electron-volts when it is in the position shown above. It passes through a uniform electric field between two oppositely charged horizontal places (Region I) and a field-free region (Region II) before eventually striking a screen at a distance of 0.08 meter from the edge of the plates. The plates are 0.04 meter long and are separated from each other by a distance of 0.02 meters. The potential difference across the plates is 250 V. Gravity is negligible

• Calculate the magnitude of the electric field E between the plates, and indicate its direction on the diagram above.

Free Response 500

Dynamics 100

• Which two arrangements of resistors shown above have the same resistance between the terminals?

A) I and IIB) I and IVC) II and IIID) II and IVE) III and IV

Dynamics 200• A lamp, a voltmeter V, an ammeter A, and a battery

with zero internal resistance are connected as shown above. Connecting another lamp in parallel with the first lamp as shown by the dashed lines would

A) Increase with the ammeter readingB) Decrease the ammeter readingC) Increase the voltmeter readingD) Decrease the voltmeter readingE) Produce no change in either meter reading

Dynamics 300

• Two capacitors are connected in parallel as shown above. A voltage V is applied to the pair. What is the ratio of charge stored on C1 to the charge stored on C2, when C1 = 1.5 C2

A) 4/9B) 2/3C) 1D) 3/2E) 9/4

Dynamics 400

• A 30-ohm resistor and a 60-ohm resistor are connected as shown above to a battery of emf 20 volts and internal resistance r. The current in the circuit is 0.8 ampere. What is the value of r?

A) 0.22 ΩB) 4.5 ΩC) 5 ΩD) 16 ΩE) 70 Ω

Dynamics 500

• If the ammeter in the circuit above reads zero, what is the resistance R?

A) 1.5 ΩB) 2 ΩC) 4 ΩD) 5 ΩE) 6 Ω

Dynamics2 100

• The combination of farad x ohm is equivalent to which of the following units?

a) Volt b) Ampere c) Second d) Watt e) Tesla

Dynamics2 200

• If a 60-watt light bulb operates at a voltage of 120 V, what is the resistance of the bulb?

a) 2 ohms b) 30 ohms c) 40 ohms d) 720 ohms e) 7200 ohms

Dynamics2 300• What is the equivalent resistance in the circuit when

the switch is in the open position?

All L have a resistance of 6 Ωa) 3 ohms b) 6 ohms c) 12 ohms d) 24 ohms e) 36 ohms

Dynamics2 400

• What is the equivalent resistance in the circuit when the switch is in the closed position?

All L have a resistance of 6 Ω

a) 24 ohms b) 10 ohms c) 8 ohms d) 6 ohms e) 4 ohms

Dynamics2 500

• A wire made of brass and a wire made of silver have the same length, but the diameter of the brass wire is 4 times the diameter of the silver wire. The resistivity of brass is 5 times greater than the resistivity of silver. If RB denotes the resistance of the brass wire and RS denotes the resistance of the silver wire, which of the following is true?

a) RB = 5/16 Rs

b) RB = 4/5 Rs

c) RB = 5/4 Rs

d) RB = 5/2 Rs

e) RB = 16/5 Rs