Grade 12

Which of the following statements about electric charges is true?

• opposite charges attract each other

• like charges attract each other

• opposite charges repel each other

• like charges have no effect on each other

What is the electrostatic force between two point charges of +1 nC and -1 nC placed 1 m apart?

• -9 × 10⁻⁹ N

• 9 × 10⁻⁹ N

• -9 × 10⁻¹² N

• 9 × 10⁻¹² N

How does the electrostatic force between two point charges change when the distance between them is doubled?

• the force decreases by a factor of 4

• the force decreases by a factor of 2

  
  

• the force increases by a factor of 4

• the force increases by a factor of 2

How does electric field strength vary with distance from a point charge?

• inversely proportional to distance

• directly proportional to distance

• directly proportional to the square of the distance

• inversely proportional to the square of the distance

Two point charges are placed 3 m apart. One charge is -1.5 nC and the other is +2nC. Calculate the electric field strength at the midpoint between the two charges.

• 13.734 N/C

• 12.891 N/C

• 13.987 N/C

• 14.567 N/C

If the distance between a point charge and a point in space is doubled, how does the electric potential at that point change, assuming all other factors remain constant?

• it reduces to a quarter

• it quadruples

• it halves

• it doubles

What type of work is done if an electron is moving opposite to the electric field.

• Negative

• Positive

• Zero

• None of the above

A point charge of 2 x 10^-6 C is placed 10 m away from another point charge in a vacuum. Calculate the electric potential at the point where the second charge is located.

• -2250 V

• -450 V

• 450 V

• 1798 V

If the area of each plate of a parallel plate capacitor is 0.01 m², the distance between the plates is 1 mm, and the relative permittivity of the dielectric is 3.0, what is the capacitance of the capacitor?

• 2.66 x 10^-9 F

• 2.66 x 10^-11 F

• 2.66 x 10^-10 F

• 2.66 x 10^-12 F

If the distance between the plates of a parallel plate capacitor is halved and the area of the plates is doubled, how does the capacitance change assuming the dielectric constant remains constant?

• the capacitance remains unchanged.

• the capacitance is quadrupled.

• the capacitance is halved.

• the capacitance is doubled.