Electric charge and field

State the SI unit of electric charge.

• Coulomb (C)

• Ampere (A)

• Ohm (Ω)

• Volt (V)

Two point charges of +3 μC and -5 μC are placed 8 cm apart. Calculate the force between them.

• 2.34 x 10^-3 N

• 1.88 x 10^-10 N

• 2.34 x 10^-9 N

• 1.88 x 10^-4 N

A charge of +2 μC is placed at the origin. Draw the electric field lines around it.

• The electric field lines will point towards the origin

• The electric field lines will form a perfect circle around the origin

• The electric field lines will be parallel to the x-axis

• The electric field lines will radiate outward from the origin.

Explain the concept of electric field lines and their significance.

• Electric field lines have no significance in the study of physics.

• Electric field lines are only visible in a vacuum.

• Electric field lines are used to measure the temperature of charged objects.

• Electric field lines help visualize the direction and strength of the electric field around charged objects.

Calculate the electric field at a point located 10 cm away from a +4 μC charge.

• The electric field at a point located 10 cm away from a +4 μC charge is 3.6 x 10⁴ N C^-1.

• The electric field at a point located 10 cm away from a +4 μC charge is 1.2 x 10⁴ N C^-1.

• The electric field at a point located 10 cm away from a +4 μC charge is 2.5 x 10⁴ N C^-1.

• The electric field at a point located 10 cm away from a +4 μC charge is 5.0 x 10⁴ N C^-1.

Which of the following is the best insulator?

• metal paper clip

• wood log

• bowl of water

• penny

In the diagram below, P is a point near a negatively charged sphere. Which direction best represents the direction of the electric field at point P?

• Right
• Left
• Up 
• Down

A point charge Q is far from all other charges. At a distance of 2 m from Q, the electric field is 20 N/C. What is the force a charge of 5 Coulombs feels?

• 4 N
• 100 N
• 40 N
• 10 N

What is the magnitude of the electric field intensity at a point where a proton experiences an electrostatic force of magnitude 2.30 x 10^-25 newton?

• 1.44 x 10^-6 N/C
• 3.68 x 10⁶ N/C
• 1.44 x 10⁴⁴ N/C
• 3.68 x 10^-44 N/C

Q_A and Q_B are two charges creating an electric field. Based on the electric field lines, we can conclude that _____________.

• Q_A and Q_B are both positive

• Q_A and Q_B are both negative

• Q_A is positive and Q_B is negative

• Q_A is negative and Q_B is positive