Test 1 Practice questions with answers (1)

Part 1: Practice Questions for Test 1

Q.1

• Question: Distance required for electrostatic force of 5.70 N between charges q1 = 26.0 μC and q2 = −47.0 μC?

• Answer: Find distance using Coulomb’s law.

Q.2

• Question: Current in lightning bolt = 2.5 × 10^4 A for 20 μs. Charge transferred?

• Answer: Charge = Current × Time = 0.50 C.

Q.3

• Question: Force between charges +3.00 × 10−6 C and −1.50 × 10−6 C at 12.0 cm?

• Answer: Force magnitude = 2.81 N at r = 0.120 m.

Q.4

• Question: Mass and charge of two equally charged particles apart by 3.2 × 10−3 m?

• Answer:

  • (a) Mass of second particle = 9.0 × 10^-7 kg.

  • (b) Magnitude of charge = 7.1 × 10^-11 C.

Q.5

• Question: Ratio q1/q2 for particle 3 with zero net force?

• Answer: Ratio derived using conditions and Coulomb’s law = 1.39 m.

Part 2: Additional Questions

Q.6

• Question: Net electrostatic force components on particle 3 with charges in Fig. 2?

• Answer:

  • (a) x-component

  • (b) y-component calculated.

Q.7

• Question: Find charge Q for particle 3 to accelerate in specific directions?

• Answer:

  • (a) Q = –83 μC for +x direction.

  • (b) Q = 55.2 μC for +y direction.

Q.8

• Question: Current of 0.300 A for 2 min through chest?

• Answer: Electrons passing through = 2.25 × 10^20.

Q.9

• Question: Total charge of 75.0 kg of electrons?

• Answer: Total charge = −1.32 × 10^11 C.

Q.10

• Question: Electrostatic force between 1.00 C point charges?

• Answer: Evaluations at different distances using Coulomb’s law.

General Concepts

Electric Field Lines

• Field lines do not cross.

• Represent paths for particles moving in electric fields.

• Point away from positive and towards negative charges.

• Density relates to field strength.

Electric Force and Charge Relationships

• Force on charge = Electric field strength × charge.

Charge Distribution and Electric Fields

• Forces depend on distance and charge quantity.