⚡ 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 resistance of 3.3 M is connected across a 500 V source. The resulting current is approximatelyAnswer: 151 µA You are measuring the current in a circuit that is operated on an 18 V battery. The ammeter reads 40 mA. Later you notice the current has dropped to 20 mA. How much has the voltage changed?Answer: 9 V The current through a flashlight bulb is 40 mA and the total battery voltage is 4.5 V. The resistance of the bulb is approximatelyAnswer: 112 Ω If you wish to increase the amount of current in a resistor from 120 mA to 160 mA by changing the 24 V source, what should the new voltage setting be?Answer: 32 V If 24 V are applied across a resistor and there are 10.9 mA of current, the resistance isAnswer: 2.2 kΩ How much resistance is needed to draw 17.6 mA from a 12 volt source?Answer: 680 Ω How much current is produced by a voltage of 18 kV across a 15 k resistance?Answer: 1.2 A A current of 200 µA through a 6.8 k resistor produces a voltage drop ofAnswer: 1.36 V Four amperes of current are measured through a 24 Ω resistor connected across a voltage source. How much voltage does the source produce?Answer: 96 V Twelve volts are applied across a resistor. A current of 3 mA is measured. What is the value of the resistor?Answer: 4 k Ω When 12 V are applied across a 68 resistor, the current isAnswer: 176 mA Approximately how much current flows through a 3.3 MΩ resistor across a 30 V source?Answer: 9 μ A A 120 V lamp-dimming circuit is controlled by a rheostat and protected from excessive current by a 3 A fuse. To what minimum resistance value can the rheostat be set without blowing the fuse? Assume a lamp resistance of 20 ohms.Answer: 20 Ω What is the approximate filament resistance of a light bulb if it operates from a 110 V source and 0.6 A of current is flowing?Answer: 183 Ω What is the approximate resistance of a rheostat if the voltage source is 18 V and the current is 220 mA?Answer: 82 Ω A 33 half-watt resistor and a 330 half-watt resistor are connected across a 12 V source. Which one(s) will overheat?Answer: 33 Ω When the pointer of an analog ohmmeter reads close to zero, the resistor being measured isAnswer: shorted In 0.025 W, there areAnswer: 25 mW A certain appliance uses 350 W. If it is allowed to run continuously for 24 days, how many kilowatt-hours of energy does it consume?Answer: 201.6 kWh A power supply produces a 0.6 W output with an input of 0.7 W. Its percentage of efficiency isAnswer: 85.7% A given power supply is capable of providing 6 A for 3.5 h. Its ampere-hour rating isAnswer: 21 Ah A 15 V source is connected across a 12 Ω resistor. How much energy is used in three minutes?Answer: 0.938 Wh At the end of a 14 day period, your utility bill shows that you have used 18 kWh. What is your average daily power?Answer: 1.286 kWh A 120 resistor must carry a maximum current of 25 mA. Its rating should be at leastAnswer: 150 mW If you used 400 W of power for 30 h, you have usedAnswer: 12 kWh A 6 V battery is connected to a 300 Ω load. Under these conditions, it is rated at 40 Ah. How long can it supply current to the load?Answer: 2,000 h In 40 kW, there areAnswer: 40,000 W If you used 600 W of power for 60 h, you have usedAnswer: 36 kWh If it takes 400 ms to use 12,000 J of energy, the power isAnswer: 30 kW How many watt-hours represent 65 W used for 18 h?Answer: 1,170 Wh