Question Library

(a) Distinguish between the forces of adhesion and cohension (b) Give one example each of the forces of adhesion and cohesion.

Explain why water in a narrow glass tube has a concave meniscus while mecury in the same tube, has a convex meniscus

(a) State two applications of electrolysis. (b) Explain what is meant by the electrochemical equivalent of copper is 3.3 x 10\(^{-7}\) kgC\(^{-1}\)

The uncertinty in determining the duration during which an electron remains in a particular energy level before returning to the ground state is 2.0 x 10\(^{-9}\)s. Calculate the uncertainty in determining its energy at that level [Take \(\frac{h}{2\pi} = h = 1.054 \times 10^{-34}\) Js]

A paralIel beam of unpolarized light is incident on a plane glass of refractive index 1.60 at an angle to the normal. If the reflected beam is completely polarized, calculate the angle of incidence of the beam.

List three observations in support of the de-Broglie's assumptions that moving particles behave like waves.

(a) State two; (i) laws of solid friction; (ii) advantages of friction; (iii) methods of reducing friction. (b) Draw and label a diagram of a pulley system with velocity ratio of 5. (c)(i) Show that the efficiency L, force ratio M.A. and the velocity ratio V.R. of a machine are related by the equation \(E = \frac{M.A.}{V.R}\) x 100%. (ii) The efficiency of a machine is 80%. Calcuate the work done by a person using the machine to raise a load of 300 kg through a height of 4 m.[ g = 10 ms\(^{-2}\) ]

(a) With the aid of ray diagrams, explain total internal reflection. (b) Describe, with the aid of a labelled diagram, the essential features of an astronomical telescope in normal adjustment. (c) A converging lens forms a real image of a real object. If the magnification is 2 and the distance between the image and the object is 90.0 cm, determine the (i) focal length of the lens; (ii) object distance for which the image would be the same size as the object.

(a)(i) Name and explain the common defects of a primary cell. (ii) State two advantages of a secondary cell over a primary cell. (b) Draw a labelled diagram to show the essential parts of a dry leclanche cell. (c)(i) Explain why six accumulators each of e.m.f 2V connected in series can be used to start the engine of a car whereas eight dry cells each of e.m.f 1.5 V connected in series cannot be used. (ii) Name the materials used for the positive terminal, the negative terminal and the electrolyte in a I. leclanche cell; II. charged lead acid accumulator.

(a) Define (i) proton number; (ii) nucleon number; (iii) isotopes. (b) A nuclide \(^A_ZX\) emits \(\beta\)-particle to form a daughter nuclide Y. Write a nuclear equation to illustrate the charge conservation. (c) The radioactive nuclei \(^{210}_{84}P_o\) emits an \(\alpha\) - particle to produce \(^{206}_{82}P_b\). Calculate the energy, in MeV, released in each disintegration. Take the masses of \(^{210}_{84}P_o\) = 209.936730 u; \(^{206}_{82}P_b\) = 205.929421 u; \(^{4}_{2}He\) = 4.001504 u; and that 1u = 931 MeV

(a) State the conditions for the equilibrium of a rigid body acted upon by parallel forces. (b)(i) Describe an experiment to determine the mass of a metre rule using the principle of moments. (ii) State two precautions necessary to obtain accurate results in the experiment described in (b)(i) above. (c) A bullet of mass 120 g is fired horizontally into a fixed wooden block with a speed of 20 ms\(^{-1}\). If the bullet is brought to rest in the block in 0.1s by a constant resistance, calculate the (i) magnitude of the resistance; (ii) distance moved by the bullet in the wood.

You are provided with a constantan wire, a 2\(\Omega\) standard resistor, an accumulator E, an ammeter A, a key K, and other necessary apparatus. Measure and record the e.m.f.of the accumulator provided. Connect a circuit as shown in the diagram above. Close the key, read and record the ammeter reading \(l_o\) when the crocodile clip is not in contact with the constantan wire. Open the key. With the clip making contact with the wire, when I = 90cm, close the key. Read and record the ammeter reading /. Evaluate l\(^{-1}\). Repeat the procedure for l= 80, 70, 60 and 50cm. In each case, read and record the ammeter reading and evaluate l\(^{-1}\). Tabulate your readings. Plot a graph of l on the vertical axis against l\(^{-1}\) on the horizontal axis. Determine the slope, s, of the graph and its intercept, c on the vertical axis. Evaluate k = \(\frac{c}{s}\). Using your graph, determine the Current i when / = 55cm. State two precautions taken to ensure accurate results. (b)i. Explain what is meant by the potential difference between two points in an electric circuit. ii. State two factors on which the resistance of a resistance wire depends.

You have been provided with a metre rule, a clamp, and a set of masses. Clamp the metre rule to the edge of the bench such that 90cm of the rule projects from the edge as shown in the diagram above. Ensure that the rule is capable of performing oscillatory motion. Fix a mass M = 50g at the free end of the rule. Deflect the rule slightly such that it performs vertical oscillation. Determine the time t for 10 complete oscillations. Calculate the period T of the oscillations and evaluate T\(^{2}\) Repeat the procedure for four other values of M = 100, 150, 200, and 250g. In each case determine and record the corresponding values of t, T, and T\(^{2}\). Tabulate your readings. Plot a graph of T\(^{2}\) on the vertical axis against M on the horizontal axis, starting both axes from the origin (0,0). Determine the slopes, of the graph and its intercept C on the vertical axis. Evaluate k = 4\(\pi\)/s. [Take \(\pi\) = \(\frac{22}{7}\)]. From your graph, determine the period T, when M= 180g. State two precautions taken to ensure accurate results. (b)i. Explain simple harmonic motion. ii. Define period and frequency, with respect to a simple harmonic motion. Precautions: l ensured that the metre rule was firmly clamped Readings were repeated Parallax was avoided when readings on the stopwatch/clock were taken. zero error was noted and corrected on the stopwatch/clock. (b)i. Simple harmonic motion is a motion in which the acceleration is proportional to the displacement from a fixed point and is directed towards the point. ii. Period is the time taken by an oscillatory body to make one complete oscillation. Frequency: is the number of complete oscillations performed in one second.

You have been provided with a rectangular glass prism, optical pins, and other necessary apparatus. Using the above diagram as a guide, carry out the following instructions: Fix the drawing paper provided to the drawing board Place the glass prism on the drawing paper and trace the outline, ABCD of the prism Remove the prism, mark a point O on AB such that AO is about one-quarter of AB Draw a normal through point O. Also draw an incident ray to make an angle i = 25 with the normal at O. Fix two pins at \(P_1\) and \(P_2\) On the incident ray. Replace the prism. Fix two other pins at \(P_3\) and \(P_4\) such that the pins appear to be in a straight line with the images of the pins at \(P_1\) and \(P_2\) when viewed through the block along DC remove the prism. Join points Pa and P4 and produce it to meet DC at 1. Also, draw a line to join Ol ( With O as center and using any Concinient radius, draw a circle to Cut the incident ray and the refracted ray at E and H respectively. Maintain this radius throughout the experiment Draw the perpendiculars EF and GH. Measure and record d= EF and I= GH. Repeat the procedure for four other values of i = 35^\circ, 45, 55^\circ, and 65^\circ respectively. In each case measure and record d and I Plot a graph of d on the vertical axis against I on the horizontal axis Determine the slope of the graph State two precautions taken to ensure accurate results. [Attach your traces to your answer booklet) (b)i. State Snell's law. ii. Calculate the critical angle for a water-air interface. [refractive index of water = \(\frac{4}{3}\)]

Use the figures above to answer the question below Which of the following diagrams represents correctly an n-p-n transistor?