Quiz on Power and Torque
1. What is a simpler way to expressing 0.000 018 A?
2. What is a simpler way to expressing 5 000 000 V?
3. An electric motor is developing 8.5kW at a speed of 900r/min. Calculate the torque available at the shaft.
4. A generating station has a daily output of 160MW h and uses 300 t (tones) of coal in the process. The coal releases 7 MJ/kg when burnt. Calculate the overall efficiency of the station.
5. A lift of 250 kg mass is raised with a velocity of 6 m/s. If the driving motor has an efficiency of 85%, calculate the input power to the motor.
6. An electric heater contains 70 liters of water initially at a mean temperature of 16 oC; 2.5kW h is supplied to the water by the heater. Assuming no heat losses, what is the final mean temperature of the water? (it takes 4185J to raise the temperature of 1 liter of water through 1oC)
7. A circuit delivers energy at the rate of 15W and the current is 13A. Determine the energy of each coulomb of charge in the circuit.
8. A current of 5 A flows in a resistor of resistance 32 . Determine the rate of heat dissipation and also the heat dissipated in 15 s.
9. A motor gives an output power of 20 kW and operates with efficiency of 85 %. If the constant input voltage to the motor is 170 V, what is the constant supply current?
10. Gives the meaning of potential difference and its unit.
11. A p.d of 6 V causes a current of 0.6 A to flow in a conductor. Calculate the resistance of the conductor.
12. Find the p.d required to pass a current of 5 A through a conductor of a resistance 10 .
13. A 960 fan is connected to a 240 V supply. Calculate the current in the fan.
14. A p.d of 1.35 V causes a current of 665 A to flow in a conductor. Calculate the resistance of the conductor.
15. A p.d of 24 V is applied to a 4.7 k resistor. Calculate the circuit current.
16. What is the voltage across a sound reducer of resistance 5 through which passes a current of 22 A.
17. What is the charged transferred in a period
2. What is a simpler way to expressing 5 000 000 V?
3. An electric motor is developing 8.5kW at a speed of 900r/min. Calculate the torque available at the shaft.
4. A generating station has a daily output of 160MW h and uses 300 t (tones) of coal in the process. The coal releases 7 MJ/kg when burnt. Calculate the overall efficiency of the station.
5. A lift of 250 kg mass is raised with a velocity of 6 m/s. If the driving motor has an efficiency of 85%, calculate the input power to the motor.
6. An electric heater contains 70 liters of water initially at a mean temperature of 16 oC; 2.5kW h is supplied to the water by the heater. Assuming no heat losses, what is the final mean temperature of the water? (it takes 4185J to raise the temperature of 1 liter of water through 1oC)
7. A circuit delivers energy at the rate of 15W and the current is 13A. Determine the energy of each coulomb of charge in the circuit.
8. A current of 5 A flows in a resistor of resistance 32 . Determine the rate of heat dissipation and also the heat dissipated in 15 s.
9. A motor gives an output power of 20 kW and operates with efficiency of 85 %. If the constant input voltage to the motor is 170 V, what is the constant supply current?
10. Gives the meaning of potential difference and its unit.
11. A p.d of 6 V causes a current of 0.6 A to flow in a conductor. Calculate the resistance of the conductor.
12. Find the p.d required to pass a current of 5 A through a conductor of a resistance 10 .
13. A 960 fan is connected to a 240 V supply. Calculate the current in the fan.
14. A p.d of 1.35 V causes a current of 665 A to flow in a conductor. Calculate the resistance of the conductor.
15. A p.d of 24 V is applied to a 4.7 k resistor. Calculate the circuit current.
16. What is the voltage across a sound reducer of resistance 5 through which passes a current of 22 A.
17. What is the charged transferred in a period