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Form 3 Physics: Heating Effect of an Electric Current Questions and Answers

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Lessons (15)

• 1.    When a current of 2.0A flows in a resistor for 10 minutes, 15,000 joules of electrical energy is dissipated. Determine the voltage across the resistor.
  2m 16s

• 2.    An electric bulb rated 40W is operating on 240V mains. Determine the resistance of its filament.
  1m 10s

• 3.    An electric heater rated 3000w is to be connected to a 240V mains supply, through a fuse 10A fuse. Determine whether the fuse is suitable or not.
  1m 26s

• 4.    An electric kettle is rated at 1.8kW, 240V.Determine the rating of the fuse that may be used in the kettle.
  1m 40s

• 5.    A hair drier is rated 2500w, 240v.Determine its resistance.
  1m 37s

• 6.    State how heating is achieved in a resistance wire.
  1m 14s

• 7.    A 60w bulb is used continuously for 36hours. Determine the energy consumed. Giving your answer in kWh
  1m 5s

• 8.    An electric bulb with a filament of resistance 480 ohms is connected to a 240v mains supply. Determine the energy dissipated in 2 minutes.
  1m 46s

• 9.    An electric bulb is rated 75w, 240v.Determine the resistance of the bulb.
  1m 20s

• 10.    A 4 ohms resistor is connected in series to a battery of e.m.f. 6v and negligible resistance. Determine the power dissipated by the resistor.
  0m 54s

• 11.    A Current I flowing through a wire of resistance R was increased seven times. Determine the factor by which the power was increased.
  2m 7s

• 12.    An electric heater is connected to the mains supply. A fault in the mains reduces the supply potential slightly. Explain the effect on the rate of heating of the heater.
  1m 16s

• 13.    A heating coil is rated 100w, 240v.What will be the power dissipated by the coil if it is connected to a 220v supply.
  1m 52s

• 14.    Two points A and B have the potential difference v volts. Q coulombs of charge flows between A and B for t seconds. Determine: i).the electrical energy transformed between the two points in terms of Q. ii).the power transformed in terms of Q and t. iii).show that the power transformed is given by P=IV.
  2m 50s

• 15.    The lighting in a house has 20 lamps each rated 60w, 240v.Determine whether a fuse rated 4A can be used in the circuit when all the lamps are put on.
  0m 0s