⚡ Electrical Engineering Solved MCQs with Answers

Practice 757 approved ⚡ Electrical Engineering questions with verified answers from the 🛠️ Engineering Essentials subject for Pakistan exams.

757 solved MCQs

A certain voltage source has the values VS = 30 V and RS = 6 . The values for an equivalent current source areAnswer: 5 A, 6 Ω A 120 Ω load is connected across an ideal voltage source with VS = 12 V. The voltage across the loadAnswer: is 12 V A 120 Ω load is connected across a voltage source with VS = 12 V and RS = 8 . The voltage across the load isAnswer: 11.25 V A 12 mA current source has an internal resistance, RS, of 1.2 k. The equivalent voltage source isAnswer: 14.4 V Find I₂. 4I₁ + 4I₂ = 2 6I₁ + 7I₂ = 4Answer: 1 A In assigning the direction of branch currents,Answer: the directions are not critical Find I₁. 4I₁ + 4I₂ = 2 6I₁ + 7I₂ = 4Answer: –0.5 A The first row of a certain determinant has the numbers 3 and 5. The second row has the numbers 7 and 2. The value of this determinant isAnswer: -29 The first row of a certain determinant has the numbers 10 and 6. The second row has the numbers 3 and 5. The value of this determinant isAnswer: 32 The expansion method for evaluating determinants isAnswer: good for second- and third-order determinants The branch current method usesAnswer: Kirchhoff's voltage and current laws When the speed at which a conductor is moved through a magnetic field is increased, the induced voltageAnswer: increases The induced voltage across a coil with 250 turns that is located in a magnetic field that is changing at a rate of 8 Wb/s isAnswer: 2,000 V For a given wirewound core, an increase in current through the coilAnswer: Increases the flux density If the cross-sectional area of a magnetic field increases, but the flux remains the same, the flux densityAnswer: decreases When the current through the coil of an electromagnet reverses, theAnswer: Direction of the magnetic field reverses What is the reluctance of a material that has a length of 0.07 m, a cross-sectional area of 0.014 m², and a permeability of 4,500 Wb/At × m?Answer: 1111 At/Wb A coil of wire is placed in a changing magnetic field. If the number of turns in the coil is decreased, the voltage induced across the coil willAnswer: decrease What is the flux density when the flux is 5.5 μ Wb and the cross-sectional area is 6 × 10⁻³ m²?Answer: 917 μ T The unit for reluctance isAnswer: At/Wb If the steel disk in a crankshaft position sensor has stopped with the tab in the magnet's air gap, the induced voltageAnswer: is zero There is 900 mA of current through a wire with 40 turns. What is the reluctance of the circuit if the flux is 400 μ Wb?Answer: 90,000 At/Wb A basic one-loop dc generator is rotated at 90 rev/s. How many times each second does the dc output voltage peak (reach maximum)?Answer: 180 What is the flux density in a magnetic field in which the flux in 0.1 m2 is 600 μ Wb?Answer: 6,000 μ T The unit for permeability isAnswer: Wb/At × m What is the magnetomotive force in a 75-turn coil of wire when there are 4 A of current through it?Answer: 300 At The direction of a magnetic field within a magnet isAnswer: from south to north When the north poles of two bar magnets are brought close together, there will beAnswer: a force of repulsion The ability of a material to remain magnetized after removal of the magnetizing force is known asAnswer: retentivity The voltage induced across a certain coil is 200 mV. A 120 Ω resistor is connected to the coil terminals. The induced current isAnswer: 1.7 mA