All Free Electrical Engineering MCQs with Answers
Every Electrical Engineering question in the bank, across all chapters, each with the correct answer and a written explanation. Free and unlimited, with no account needed.
3,143 questions · page 9 of 158
- A. resistance
- B. resistivity
- C. conductivity
- D. conductance
Explanation: In the electric-magnetic circuit analogy, permeability indicates how easily magnetic flux is established, just as conductivity indicates…
Correct answer: conductivity162. When 4 volts e.m.f. is applied across a 1 farad capacitor, it will store energy of_____________?
- A. 2 joules
- B. 4 joules
- C. 6 joules
- D. 8 joules
Explanation: Capacitor energy is W = ½CV² = ½ × 1 × 4² = 8 joules. The factor ½ is essential, so 4 joules would incorrectly equal CV² without this…
Correct answer: 8 joules- A. 50 pF
- B. 100 pF
- C. 150 pF
- D. 200 pF
Explanation: Capacitances in parallel add directly, so the required capacitor is 150 − 50 = 100 pF.
Correct answer: 100 pF- A. 800 uC
- B. 900 uC
- C. 1200 uC
- D. 1600 uC
Explanation: Using Q = CV, the charge is 6 μF × 200 V = 1200 μC. Keeping the microfarad unit gives the answer directly in microcoulombs.
Correct answer: 1200 uC- A. Gauss's law
- B. Kirchhoff s law
- C. Faraday's law
- D. Lenz's law
Explanation: Gauss’s law states that the closed-surface integral of electric displacement is equal to the enclosed charge, ∮D·dS = Q.
Correct answer: Gauss's law- A. 36 x 10fa
- B. 36 x 10^7 N
- C. 36 x 10^8 N
- D. 36 x 10^9 N
Explanation: Using Coulomb’s law, F = kq₁q₂/r² = 9 × 10⁹ × 1 × 1/(0.5)² = 36 × 10⁹ N. Thus the force is 36 × 10⁹ newtons.
Correct answer: 36 x 10^9 N- A. reluctance
- B. conductance
- C. susceptance
- D. elastance
Explanation: Capacitance measures charge stored per unit voltage, C = Q/V; its inverse, V/Q, is called elastance.
Correct answer: elastance- A. Electric
- B. Magnetic
- C. Both (A) and (B)
- D. None of the above
Explanation: A capacitor stores energy in its electric field, formed by separated charges on its plates.
Correct answer: Electric- A. current
- B. voltage
- C. potential gradient
- D. charge
Explanation: A body’s net deficiency or excess of electrons is its electric charge. Current is the rate of charge flow, while voltage is the energy…
Correct answer: charge- A. smaller
- B. greater
- C. both (A) and (B)
- D. none of the above
Explanation: At an interface between dielectric materials, the normal electric flux density is the same, while E = D/ε.
Correct answer: greater- A. 50 joules
- B. 150 joules
- C. 200 joules
- D. 250 joules
Explanation: Capacitor energy is W = ½CV² = ½ × 5 × 10⁻⁶ × (10,000)² = 250 J. The voltage is squared, so even a small capacitance stores substantial…
Correct answer: 250 joules- A. electric flux
- B. electric flux density
- C. magnetic flux density
- D. electric charge densityElectricity
Explanation: Electric flux is the total number of electric field lines, historically called Faraday tubes, passing through a surface.
Correct answer: electric flux- A. 0.56 x 10^15 m/s2
- B. 1.5 x 10^15 m/s2
- C. 1.6 x 10^15 m/s2
- D. 1.76 x 10^15 m/s2
Explanation: The field between the plates is E = V/d = 100/0.01 = 10,000 V/m. Using a = eE/m for an electron gives approximately 1.76 × 10¹⁵ m/s²…
Correct answer: 1.76 x 10^15 m/s2- A. pholoelectric effect
- B. chemical effect
- C. magnetic effect
- D. induction
Explanation: Charging an initially uncharged conductor by bringing a charged body near it, without contact, is electrostatic induction.
Correct answer: induction- A. Newton
- B. Faraday
- C. Michale
- D. None of the above
Explanation: A unit tube of electric flux is called a Faraday tube. The term refers to one electric flux unit, whereas Newton is a unit of force.
Correct answer: Faraday176. The value of E within the field due to a point charge can be found with the help of___________?
- A. Faraday's laws
- B. Kirchhoff s laws
- C. Coulomb's laws
- D. none of the above
Explanation: The electric field intensity due to a point charge follows Coulomb’s law, E = Q/(4πεr²).
Correct answer: Coulomb's laws- A. Electric intensity
- B. Electric flux
- C. Magnetic flux
- D. Magnetic flux density
Explanation: Electric intensity is the negative gradient of electric potential, expressed as E = −∇V.
Correct answer: Electric intensity- A. increases
- B. decreases
- C. remains unaltered
- D. none of the above
Explanation: For practical solid dielectrics, dielectric strength generally decreases as thickness increases because larger volumes contain more…
Correct answer: decreases- A. electric flux
- B. magnetic flux density
- C. potential gradient
- D. none of the above
Explanation: Electric intensity is the force per unit charge and equals the potential gradient, written as E = -dV/dr.
Correct answer: potential gradient- A. Inductance
- B. Capacitance
- C. Potential gradient
- D. None of the above
Explanation: Capacitance causes voltage to change gradually because i = C dv/dt; a finite current cannot produce an instantaneous voltage change across…
Correct answer: Capacitance