Free Electrostatics MCQs with Answers
831 Electrostatics MCQs from Physics, each with the correct answer and a written explanation of why it is correct. Free and unlimited, with no account needed.
Electrostatics describes forces between charges through Coulomb's law, electric fields and field intensity, then uses electric potential to measure energy per unit charge. Capacitors store charge and electrical energy, with capacitance depending on geometry and dielectric material, not simply on the amount of charge present.
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Read the Electrostatics notesFree MDCAT chapter notes with key terms831 questions · page 8 of 42
- A. Nm2C2
- B. N-1 mC²
- C. NmC¹
- D. N-1 m-2C²
Explanation: Electrical force is given by F=q1q2/(4 πϵo r2)So, ϵo = q1q2/(4 πF r2).Here, q1 and q2 are charges, r is the distance between then and ϵo…
Correct answer: N-1 m-2C²- A. A
- B. B
- C. C
- D. D
Explanation: As 1 and 2 have attract eachother they have opposite charges. And 1 and 3 repel eachother so they have the same charge.
Correct answer: C- A. A
- B. B
- C. C
- D. D
Explanation: The electric potential due to a point charge is V=kQ/r. Where r is the distance between the charges and Q is the magnitude of the charge.
Correct answer: D- A. 8j
- B. 16j
- C. 4 x 10^-3 j
- D. 2 x 10^-3 j
Explanation: By using the formula U= ½ CV2Where C= 1 micro farad and V= 4000VU= ½ x (1 x 10-6) x (4000)2= 8
Correct answer: 8j- A. √2 c
- B. 2c
- C. c/√2
- D. c/2
Explanation: The capacitance of a parallel plate capacitor with a dielectric material between the plates is given by the formula:C= k. ε0.
Correct answer: c/2- A. C
- B. C/2
- C. 0
- D. 2C
Explanation: When a metal plate of thickness half the separation between the capacitor plates is inserted between the plates, the new capacitance can…
Correct answer: 2C- A. -q
- B. +q
- C. -2q
- D. +4q
Explanation: Let's denote the two charges as +4q and q and the distance between them as 2d.
Correct answer: +4q- A. acquired excess of electrons
- B. lost some protons
- C. acquired some electrons and lost a lesser number of protons
- D. lost some positive ions
Explanation: When a solid body is negatively charged by friction, it means that it has gained electrons from the material it rubbed against.
Correct answer: acquired excess of electrons- A. N/C
- B. V/m
- C. J/C
- D. J/C.m
Explanation: The correct unit of electric field is newtons per coulomb (N/C) or volts per meter (V/m).
Correct answer: J/C.m- A. 6.2×10^18
- B. 5.2×10^18
- C. 6.2×10^19
- D. 5.2×10^19
Explanation: The charge of one electron is approximately 1.6×10^−19coulombs. Therefore, to have a total charge of one coulomb, we would need…
Correct answer: 6.2×10^18- A. Work is done by the electric field
- B. Energy is used from some outside source
- C. The strength of the field is decreased
- D. The energy of the system is decreased
Explanation: When a charge is moved against the Coulomb force of an electric field, energy has to be supplied from an external source to perform this…
Correct answer: Energy is used from some outside source- A. Zero
- B. 8 N (repulsive)
- C. 8 N (attractive)
- D. 16 N (attractive)
Explanation: After giving each charge a negative charge of -2 coulombs, the net charge of the system becomes +4 coulombs( F= K(q1q2)/r^2 ) since the +2…
Correct answer: 16 N (attractive)- A. The same as the field at the surface
- B. Greater than the field at the surface
- C. Less than the field at the surface but not zero
- D. Less than the field at the surface but not zero(d) Zero
Explanation: In a hollow conducting sphere, the electric field inside the sphere is zero.
Correct answer: Less than the field at the surface but not zero(d) Zero154. Conductivity is the
- A. reciprocal of current density
- B. reciprocal of resistivity
- C. reciprocal of resistance
- D. same as current
Explanation: Conductivity (σ) is the reciprocal of resistivity (ρ), which is a measure of how strongly a material opposes the flow of electric current.
Correct answer: reciprocal of resistivity- A. E
- B. E/2
- C. zero
- D. infinity
Explanation: When a cell is open-circuited (no external load connected), the terminal potential difference is equal to the electromotive force (EMF) of…
Correct answer: E- A. σ/2εο
- B. σ/60
- C. σ/εο
- D. zero
Explanation: Between two infinite parallel plates with opposite charge densities, the electric fields due to each plate cancel each other out in the…
Correct answer: zero- A. slowly
- B. quickly
- C. with medium speed
- D. with constant speed
Explanation: When RC is small, the time constant τ=RC is small as well. A small time constant indicates that the capacitor will charge and discharge…
Correct answer: quickly- A. C/Nm
- B. C^2/(Nm)²
- C. Nm²/C^2
- D. C^2/Nm²
Explanation: The SI unit of permittivity of free space (ϵ0 ) is (d) C^2/Nm².It is a measure of a material's ability to permit the flow of electric…
Correct answer: C^2/Nm²- A. 4F
- B. F/2
- C. 2F
- D. F/4
Explanation: When a medium of dielectric constant 4 is introduced between the charges, the force between them decreases by a factor of the dielectric…
Correct answer: F/4- A. increases by a factor k
- B. decreases by a factor k
- C. increases by a factor k^2
- D. decreases by a factor k^2
Explanation: The capacitance C of a capacitor is directly proportional to the dielectric constant k of the material between its plates.
Correct answer: increases by a factor k