Electrical engineering - math word problems - last page

Number of problems found: 213

Heating Water with Coils
The smaller heating coil heats the water in 30 hours and the larger one in 20 hours. How long will it take to heat the water if both coils are switched on simultaneously, but the smaller coil breaks down after 8 hours?
Wire length
One hundred twenty wire turns are wound together on a cylindrical rod (r = 2 cm). How long is the wire when 10 cm hangs freely at each end?
Vacuum efficiency
Determine the efficiency of a vacuum cleaner with a power input of 1.2 kW when the suction power is 360 W.
Efficiency
What is the power output of a kettle 2 kW with an efficiency of 90%?
Resistance
Determine the bulb's resistance with the current 200 mA and is in a regular lamp (230 V).
Aluminum wire
Aluminum wire of 3 mm diameter has a total weight of 1909 kg and a density of 2700 kg/m³. How long is the wire bundle?
Electrics - conductor
The wire is 107 meters long at 0 °C, and at every temperature increase of 1 °C, the length increases by 0.15 mm per 1 m length of wire. Determine a function that represents the wire's overall length as a temperature function. What is the length of the wir
Efficiency
A certain device consumes 50 kW and delivers 17 kW. Find its efficiency.
Gain
Find the gain whenever the output power is 18x the input power.
Decibel
A circuit has an input power of 73 mW. Its output power is 18 mW. What is the loss in decibels?
Resistors
Two resistors connected in parallel give a combined resistance of $R1 Ω, and connected in series give a combined resistance of $R2 Ω. Determine the resistance of each resistor.
Wiring
A conduit has a cross-section of 54 mm². Is it possible to fit 6 conductors each with a cross-section of 6.7 mm² inside it?
Electronics: Resistors in parallel
Concerning calculating the resistance of the parallel combination of resistors: (1)/(R) = (1)/(R₁) + (1)/(R₂) Calculate the R, if R₁ = 17Ω a R₂ = 20Ω

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