Get premium membership and access questions with answers, video lessons as well as revision papers.
a) P = VI I = P/V = 20/240 =0.437A
b) From Ohm’s law, V =IR R=V/I =240/0.437 = 575.95?
Moraa orina answered the question on April 10, 2018 at 17:48
- A 5.5 kW immersion heater is used to heat water. Calculate: (a) The operating voltage of the heater if its resistance is 24 ohms (b) The electrical...(Solved)
A 5.5 kW immersion heater is used to heat water. Calculate:
a) The operating voltage of the heater if its resistance is 24?
b) The electrical energy converted to heat energy in 2 hours.
Date posted: April 10, 2018. Answers (1)
- Find the energy dissipated in 5 minutes by an electric bulb with a filament of resistance of 500 ohms connected to a 240V supply. { ans. 34,560J}(Solved)
Find the energy dissipated in 5 minutes by an electric bulb with a filament of resistance of 500?
connected to a 240V supply.
Date posted: April 10, 2018. Answers (1)
- An electrical bulb is labeled 20W, 240V. Calculate:
a) The current through the filament when the bulb works normally
b) The resistance of the filament used...(Solved)
An electrical bulb is labeled 20W, 240V. Calculate:
a) The current through the filament when the bulb works normally
b) The resistance of the filament used in the bulb.
Date posted: April 10, 2018. Answers (1)
- In an experiment to determine the resistance of a nichrome wire using the metre bridge, the balance
point was found to be at the...(Solved)
In an experiment to determine the resistance of a nichrome wire using the metre bridge, the balance
point was found to be at the 40cm mark. Given that the value of the resistor to the right is 30Ω, calculate
the value of the unknown resistor R.
Date posted: April 10, 2018. Answers (1)
- Two conductors A and B are such that the cross section area of A is twice that of B and the length of B is...(Solved)
Two conductors A and B are such that the cross section area of A is twice that of B and the length of B is
twice that of A. If the two are made from the same material, determine the ratio of the resistance of A to
that of B.
Date posted: April 10, 2018. Answers (1)
- Calculate the current flowing through a 8 ohms device when it is connected to a 12V supply.(Solved)
Calculate the current flowing through a 8? device when it is connected to a 12V supply.
Date posted: April 10, 2018. Answers (1)
- Find the separation distance between two plates if the capacitance between them is 1.0 * 2-12C and the
enclosed area is 5.0 cm5. Take e0...(Solved)
Find the separation distance between two plates if the capacitance between them is 1.0 * 2-12C and the
enclosed area is 5.0 cm5. Take ε0 = 6.85 * 2-12Fm-1. { d = 1.425 * 2-4 m}
Date posted: April 10, 2018. Answers (1)
- What is the average current that flows when a 720µF capacitor is charged to 2V in 0.03s?(Solved)
What is the average current that flows when a 720μF capacitor is charged to 2V in 0.03s?
Date posted: April 10, 2018. Answers (1)
- How much charge is stored by a 300µF capacitor charged up to 12V? give your answer in (a) µC (b) C
{ans. 3600µC/0.0036C}(Solved)
How much charge is stored by a 300μF capacitor charged up to 12V? give your answer in (a) μC (b) C
{ans. 3600μC/0.0036C}
Date posted: April 10, 2018. Answers (1)
- In experiment, the diameter of oil patch was 21 cm for an oil drop of radius 0.28 mm. Determine the diameter of oil molecule(Solved)
In experiment, the diameter of oil patch was 21 cm for an oil drop of radius 0.28 mm. Determine the diameter of oil molecule.
Date posted: April 10, 2018. Answers (1)
- State the applications of static charges(Solved)
State the applications of static charges
Date posted: April 10, 2018. Answers (1)
- Explain how lightning arrestors work(Solved)
Explain how lightning arrestors work.
Date posted: April 10, 2018. Answers (1)
- Explain how an electric wind works(Solved)
Explain how an electric wind works
Date posted: April 10, 2018. Answers (1)
- What are the applications of photoemission?(Solved)
What are the applications of photoemission?
Date posted: April 10, 2018. Answers (1)
- If the air temperature and the wet bulb depression are 30 degrees Celcius and 8.5 degrees celcius. What is the wet bulb temperature?(Solved)
If the air temperature and the wet bulb depression are 30 degrees Celcius and 8.5 degrees celcius. What is the wet bulb temperature?
Date posted: April 9, 2018. Answers (1)
- An anemometer 10 m above the ground recorded a wind velocity of 1.5 m/s. What is the estimated wind velocity at 2 m above the...(Solved)
An anemometer 10 m above the ground recorded a wind velocity of 1.5 m/s. What is the estimated wind velocity at 2 m above the surface?
Date posted: April 9, 2018. Answers (1)
- A wheel and axle is used to raise a load of 140N by a force of 20N applied to the brim of the wheel. If...(Solved)
A wheel and axle is used to raise a load of 140N by a force of 20N applied to the brim of the wheel. If the
radii of the wheel and axle are 70cm and 5cm respectively, calculate the mechanical advantage, velocity
ratio and efficiency of the system.
Date posted: April 9, 2018. Answers (1)
- . A driving gear having 25teeth engages with a second gear with 20teeth. A third gear with 30 teeth on the
same shaft as the...(Solved)
A driving gear having 25teeth engages with a second gear with 20teeth. A third gear with 30 teeth on the
same shaft as the second one engages with a fourth gear having 60teeth. Find:
a) The total velocity ratio of the system.
b) The mechanical advantage of the system if its efficiency is 85%.
Date posted: April 9, 2018. Answers (1)
- A man uses an inclined plane to lift a 81kg mass through a vertical height of 1.0m. Given that the angle of
inclination of the...(Solved)
A man uses an inclined plane to lift a 81kg mass through a vertical height of 1.0m. Given that the angle of
inclination of the plane is 300 and its efficiency is 75%, determine:
a) The effort needed to move the load up the inclined plane at a constant velocity.
b) The workdone against friction in raising the mass through the height of 1.0m.
Date posted: April 9, 2018. Answers (1)
- A machine whose velocity ratio is 8 is used to lift a load of 300N. The effort required is 60N. calculate:
a) The mechanical advantage of...(Solved)
A machine whose velocity ratio is 8 is used to lift a load of 300N. The effort required is 60N. calculate:
a) The mechanical advantage of the machine.
b) The efficiency of the machine.
Date posted: April 9, 2018. Answers (1)