# Unit conversion + electrical engineering - math problems

#### Number of problems found: 16

• Current in the conductor Calculate the current in the conductor (in mA) if it is connected to a 4.5 V voltage source and its resistance is 20 (ohm).
• Mains voltage How much electric current flows through the appliance with a resistance of 40kΩ, which is connected to the mains voltage (230 V)?
• Copper Cu wire Copper wire with a diameter of 1 mm and a weight of 350 g is wound on a spool. Calculate its length if the copper density is p = 8.9 g/cm cubic.
• Closed circuit In a closed circuit, there is a voltage source with U1 = 12 V and with an internal resistance R1 = 0.2 Ω. The external resistance is R2 = 19.8 Ω. Determine the electric current and terminal voltage.
• Energy consumption The device is connected to 230V and draws 3.5A current. Power consumption is 1932kJ. How many minutes has this device been in operation?
• Cooker A current of 2A passes through the immersion cooker at a voltage of 230V. What work do the electric field forces in 2 minutes?
• The copper wire The copper wire bundle with a diameter of 2.8mm has a weight of 5kg. How many meters of wire is bundled if 1m3 of copper weighs 8930kg?
• Orlík hydroelectric plant The Orlík hydroelectric power plant, built in 1954-1961, consists of four Kaplan turbines. For each of them, the water with a flow rate of Q = 150 m3/s is supplied with a flow rate of h = 70.5 m at full power. a) What is the total installed power of the p
• Effective and mean voltage A voltage divider consisting of resistors R1 = 103000 Ω and R2 = 197000 Ω is connected to the ideal sine wave voltage source, R2 is connected to a voltmeter which measures the mean voltage and has an internal resistance R3 = 200300 Ω, the measured value i
• Resistance A resistor having an electrical resistance of 1.5 k ohms passes an electrical current of 0.1 A. Calculate what voltage is between the terminals of the resistor.
• Resistance of the resistor The resistor terminals have a voltage of 20 V and a current of 5 mA is passed through. What is the resistance of the resistor?
• Resistance Determine the resistance of the bulb with current 200 mA and is in regular lamp (230V).
• 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?
• Electronics: Resistors in parallel From relation for calculating the resistance of parallel combination of resistors: ? Calculate the R, if R1 = 2Ω a R2 = 15Ω
• Copper winding Calculate the current flowing through the copper winding at an operating temperature of 70°C. Celsius, if the winding diameter is 1.128 mm and the winding length is 40 m. The winding is connected to 8V.
• RC time constant You introduced 1 Coulomb worth of electrons into the inner volume of a dielectric material with ϵr=6. 30 minutes later, you found that only 36.79% of the electrons were in the inner volume. Determine the conductivity σ of the dielectric material.

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