Physics Past Questions and Answers

A capacitor of capacitance 25µF is connected to an a.c power source of frequency 200/Ï€Hz. Calculate the reactance of the capacitor

During the electrolysis of copper (II) tetraoxosulphate (VI) solution, an ammeter shows a steady reading of 1A for 30minutes while 6.6 x \(10^{-4}\)kg of copper is liberated. Calculate the error in the ammeter The electrochemical equivalent of copper is 3.30 x \(10^{-7}kgC{-1}\)

In a nuclear reaction, the mass defect is 2 x \(10^{-6}\)g. Calculate the energy released given that the velocity of light is 3 x \(10^{8}ms^{-1}\)

An atom radiates 1.5 x \(10^{-19}\)J of energy when an electron jumps from one energy level to another. What is the wavelength of the emitted radiation? (Planck’s constant =6.6 x \(10^{-34}\)Js. Speed of light in air=3 x \(10^{8}ms^{-1}\)

(a) Explain the term work
(b) Draw a diagram of a pulley system with a velocity ratio of 5.
(c) A man pulls up a box of mass 70kg using an inclined plane of effective length 5m onto a platform 2.5m high at uniform speed. If the frictional force between the box and the plane is 100N, draw the diagram of all the forces acting on the box when in motion and calculate the
(i) minimum effort applied in pulling up the box
(ii) velocity ratio of the plane
(iii) mechanical advantage of the plane
(iv) efficiency of the plane
(v) energy lost in the system
(vi) work output of the man
(vii) total power developed by the man given that the time taken to raise the box onto the platform is 50s. (g = 10ms\(^{-2}\)).