Physics Past Questions and Answers

List three advantages of p - n junetion diode over diode valve.

(a) State two deductions that can be made from a displacement-time graph.<br/>(b) If the distance beween two equal masses is doubled and their individual masses are also doubled, what would happen to the force between them? Support your answer quantitatively.<br/>(c) State two factors that affect the maximum height attained by a bullet fired from a gun.<br/>(d) State two practical examples of mechanical resonance. A body is released from rest at the top of a plane inclined at 30° to the horizontal and 4.0 m high. If the coefficient of friction between the body and the plane is 0.3, calculate the time the body takes to reach the bottom of the plane.

(a) Define stable equilibrium as applied to a rigid body.<br/>(b) Sketch a block and tackle system of pulleys with a velocity ratio of 3.<br/>(c) At the beginning of a race, a tyre of volume 8.0 x 10\(^{-4}\) at 20°C-has a gas pressure of 4.5 x 10\(^5\) Pa. Calculate the temperature of the gas in the tyre at the end of the race if the pressure has risen to 4.6 x 1 0\(^5\) Pa.<br/>(d)(i)<br/><table class='tbn'><tbody><tr><td> </td><td> Ice point273k </td><td> 373kSteam point </td></tr><tr><td> Resistance/\(\Omega\) </td><td> 5.67 </td><td> 7.75 </td></tr><tr><td> Pressure/Pa </td><td> 7.13 x 10\(^4\) </td><td> 9.74 x 10\(^4\) </td></tr></tbody></table><br/><br/><br/><br/>The table above shows readings of the resistance and pressure of a platinum resistance thermometer and a constant-volume gas thermometer respectively, when immersed in the same liquid bath. Use this data to determine the temperature of the bath on the: (\(\alpha\)) resistance thermometer; (\(\beta\)) gas thermometer<br/>(ii) By what percentage is the temperature measured on the platinum resistance thermometer in error?

(a) What is a wavefront?<br/>(b) (i) State two practical uses of glass prisms.<br/>(ii) List two factors that determine the deviation of a ray of light travelling from air into a triangular glass prism.<br/>(iii) Sketch a graph to illustrate the variation of the angle of deviation d, with that of incidence, i, for a ray of light travelling from air into a triangular glass prism. Indicate on the graph the point at which the angle of incidence equal to the angle of emergence e.<br/> <br/>(c) (i) Draw and label a diagram of an astronomical telescope in normal adjustment.<br/>(ii) The angular magnification of an astronomical telescope in normal adjustment is 5. If the focal length of the objective is 100cm, calculate the:<br/>(\(\alpha\)) focal length of the eyepiece;<br/>(\(\beta\)) length of the telescope.

(i) What is dielectric?<br/>(ii) A parallel plate capacitor consists of two plates each of area 9.6 x 10\(^{-2}\)m\(^2\), separated by a dielectric of thickness 2.25 x 10\(^{-3}\) and dielectric constant 900. Calculate the capacitance of the capacitor. [ \(\varepsilon_o\) = permittivity of free space = 8.85 x 10\(^{-12}\)Fm\(^{-1}\)]<br/>(b) (i) Which of the following devices has a higher resistance; an ammeter or a voltmeter? Give a reason for your answer.<br/>(ii)<br/><br/>The resistance of the voltmeter in the circuit diagram illustrated above is 800\(\Omega\), Calculate the voltmeter reading.<br/>(c)<br/><br/>A battery of negligible internal resistance is connected to a set of resistors as illustrated in the circuit diagram above. Determine the equivalent resistance of the circuit.<br/><br/>