Electricity Review

Electricity Review

1) A neutral piece of fur is rubbed along a neutral plastic rod. The rod gains a charge of +4.0 C. Which of the following is true?

A) The fur gains a charge of +4.0 CB) The protons moved from the rod to the fur.C) The fur has gained electrons.D) The rod and fur now repel.E) This is an example of charging by contact.

2. The neutral rod gained a charge of +4.0 C. Which of the following statements is true?

A) The rod lost 2.5*1013 electronsB) The rod lost 2.5*1019 electronsC) The rod lost 4.0*10-6 electronsD)The rod lost 4.0*106 electronsE) The rod lost 6.4*10-25 electrons

3. Two identical conducting spheres are charged. Sphere A has a charge of +2μC and sphere B has a charge of -8μC. The two spheres touch each other. Which best describes what happened.

A) Negative charge moved from sphere B to sphere A until sphere B had a net charge of zero.

B) Positive charge moved from Sphere A to sphere B until sphere A had a net charge of zero.

C) Negative charge moved from sphere B to sphere A until the two spheres had equal charge.

D) Positive charge moved from sphere A to sphere B until the two spheres had equal charge.

E) Negative charge moved from sphere B to sphere A and positive charge moved from sphere A to sphere B until the two spheres had equal charge.

4. Two identical conducting spheres are charged. Sphere A has a charge of +2.00μC and sphere B has a charge of -8.00μC. The two spheres touch each other and then are pulled apart. To make sphere A neutral you should:

A) Add 3.75 x 1013 electronsB) Remove 3.75 x 1013 electronsC) Add 1.88 x 1013 electronsD) Remove 1.88 x 1013 electronsE) Do nothing – the sphere is already neutral.

5. Three charges are aligned as shown below.

What is the magnitude of the force on the +2.0 C charge?A) 1.4 NB) 0.80 NC) 0.60 ND) 0.20 NE) 0 N

+4.0 C-3.0 C +2.0 C

0.30 m 0.30 m

6. Two charges are aligned as shown below.

What is the electric field at point X?

A) 0 N/CB) 1.0*105 N/C to the leftC) 3.0*105 N/C to the leftD) 4.0*105 N/C to the leftE) 7.0*105 N/C to the left

+4.0 C-3.0 C Point X

0.30 m 0.30 m

7. Which of the following statement is false?

A) A positive charge experiences a force in the direction of the electric field.

B) A positive charge moving against the electric field gains electric potential energy.

C) Electric field lines never cross.D) Electric field lines start at a negative or infinity.E) The density of electric field lines is related to the

strength of the electric field

8. A parallel plate capacitor has an electric field of 0.50 N/C in the direction shown below.

Which is the positive of the two plates?A) The top plate.B) The bottom plate.C) It depends on the type of charge placed between the plates.D) It depends on the distance between the plates.E) They both have the same charge.

E


Where would a charge have the highest EPE due to the electric field?A) At the top plate.B) At the bottom plate.C) Directly between the plates.D) It depends on the type of charge placed between the plates.E) The charge has no EPE anywhere between the plates

E


What charge should a 2.5*10-5 kg drop of oil have to stay suspended between the plates? (Include gravity)A) +5.0*10-5 CB) +5.0*10-4 CC) -5.0*10-5 CD) -5.0*10-4 CE) -1.3*10-4 C

E

11. The resistance of a bagel toaster is 15 Ω. To prepare a bagel, the toaster is plugged into a standard 120-V outlet.

How much power does the toaster consume?

A) 8.0 WB) 15 WC) 120 WD) 960 WE) 1800 W


Find the energy consumed in the 1.5 minutes it takes to toast a bagel.

A) 1.4 JB) 180 JC) 1400 JD) 11000 JE) 86000 J


How much charge passes through the toaster in 1.5 minutes?

A) 12 CB) 120 CC) 720 CD) 960 CE) 86000 C

14. You are given two resistors with different resistances and a battery. Indicate which circuit arrangement best answers the question.

Which arrangement has the greatest total resistance?

A) SeriesB) ParallelC) Same for both


Which arrangement has the same current in each resistor?



Which arrangement draws the greatest current from the battery?



Which arrangement has the same voltage drop across each resistor?



Which arrangement uses up the battery faster?


19. The current in a 47-Ω resistor is 0.12 A. This resistor is in series with a 28-Ω resistor, and the series combination is connected across a battery. What is the battery voltage?

a)5.6 Vb)3.4 Vc)9.0 Vd)4.5 V

20.The current in a series circuit is 15.0 A. When an additional 8.00-Ω resistor is inserted in series, the current drops to 12.0 A. What is the resistance in the original circuit?

A) 8.00-ΩB) 24.0-ΩC) 32.0-ΩD) 40.0-Ω

21. Two identical light bulbs are connected to identical batteries in two different ways. In method A the bulbs are connected in parallel, and the parallel combination is connected between the one battery's terminals. In method B the bulbs are connected in series, and the series combination is connected between the other battery's terminals. What is the ratio of the power supplied by the battery in method A to the power supplied in method B?

A) ¼B) 4C) ½D) 1

22.Two resistors, 42.0 and 64.0 Ω, are connected in parallel. The current through the 64.0-Ω resistor is 3.00 A. Determine the current in the other resistor.

a. 1.97 Ab. 3.00 Ac. 4.57 Ad. 4.97 Ae. 7.57 A

23. Two resistors, 42.0 and 64.0 Ω, are connected in parallel. The current through the 64.0-Ω resistor is 3.00 A. What is the total power supplied to the two resistors?

a.192 Wb.318 Wc.576 Wd.877 We.1450 W

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Electricity Review