Test on Electrostatics and Electromagnetism

Question 1: An electric dipole placed in a uniform electric field experiences a net force that causes it to accelerate.

A. Ano

B. Ne

Explanation: According to the study materials, the net force on an electric dipole in a uniform electric field is given by F_net = qE + (-q)E = 0. Therefore, a net force causing acceleration is not experienced by the dipole in a uniform field.

Question 2: The electric field inside a conductor in electrostatic equilibrium is zero.

A. Ano

B. Ne

Explanation: According to the study materials, under '4.4 Key Applications of Gauss's Law', point 5 states: 'The electric field inside a conductor is zero ( E = 0 ).'

Question 3: Which of the following statements accurately describes a unit of electric charge as defined in the study materials?

A. The SI unit for electric charge is the Volt (V).

B. One microcoulomb (μC) is equivalent to 1 × 10⁻⁹ C.

C. One picocoulomb (pC) is equivalent to 1 × 10⁻¹² C.

D. One Coulomb (C) corresponds to 1.60 × 10⁻¹⁹ electrons.

Explanation: According to the study materials, the SI unit of charge is the Coulomb (C), not the Volt. One microcoulomb (μC) is 1 × 10⁻⁶ C, not 1 × 10⁻⁹ C. One Coulomb (C) corresponds to 6.25 × 10¹⁸ electrons, not 1.60 × 10⁻¹⁹ electrons. The statement that one picocoulomb (pC) is equivalent to 1 × 10⁻¹² C is correct, as stated in the 'Units of Charge' section.

Question 4: Which of the following statements correctly describes the electric field produced by a single negative point charge?

A. The field vectors point radially outward from the charge.

B. The field vectors point radially inward toward the charge.

C. The field strength decreases linearly with the distance from the charge.

D. The field strength is independent of the magnitude of the charge.

Explanation: According to the study materials, for negative charges (q < 0), electric field vectors point radially inward. The electric field strength is inversely proportional to the square of the distance (E = k q/r^2), not linearly decreasing, and it is directly proportional to the magnitude of the charge.

Question 5: Introducing a dielectric material with a dielectric constant K between the plates of a parallel-plate capacitor reduces its capacitance.

A. Ano

B. Ne

Explanation: Capacitance C for a parallel-plate capacitor with a dielectric is given by C = K ε_0 A / d, where K is the dielectric constant. Since K is typically greater than 1, introducing a dielectric material increases the capacitance, it does not reduce it.