In the diagram above, a bulb is lit by drawing 2.0A from 440V a.c. source. Calculate the cost of keeping the bulb on for two days at $0.40 per kilowatt-hour.
A wire of cross-sectional area 2π x 10\(^-{8}\) m\(^2\) and resistivity 1.1 x 10\(^-{8}\) Ω m, has a resistance of 21Ω.
Calculate the length of the wire. [π=22/7]
Which of the following statements best describes the particles in a solid at room temperature? They are
A man weighing 200 N runs up a staircase in 5s. If the height of the staircase is 9 m, calculate the power of the man.
A rotating disc contains a set of holes in a circle. An air jet is directed onto the holes and a note of frequency 480 Hz is produced. If the number of holes is 20, calculate the speed of rotation of the disc.
