Question Library

a) On what principle does lighting in a fluorescent tube operate? (b) State two factors which determine the colour of light produced in a fluorescent tube.

(a) Define electrolysis. (b) Classify each of the following substances as an electrolyte or a non-electrolyte (i) sugar solution; (ii) kerosene; (iii) alkaline solution (iv) lemon fruit juice.

(a) State Heisenberg's Uncertainty Principle. (b) State one phenomenon that can only be explained in terms of the wave nature of light.

(a) A particle moves on a straight path with an initial speed u and final speed v in time t. Show that the total distance X covered by the particle is given by \(x = ut + \frac{1}{2}at^2\) where a is the magnitude of acceleration (b) State; (i) Newton's second law of motion (ii) the principle of conservation of energy (iii) the law of floatation. (c) Consider a balloon of mass 0.030 kg being inflated with a gas of density 0.54 kg m\(^{-3}\). What will be the volume of the balloon when it just begins to rise in air of density 1.29 kg m\(^{-3}\)? [ g = 10 ms\(^{-2}\)]

(a) State two differences between boiling and evaporation. (b) A closed inexpansibie vessel contains air saturated with water vapour at 77^\circC. The total pressure in the vessel is 1007 mmHg. Calculate the new pressure in the vessel if the temperature is reduced 1.2 27^\circC. [ The s.v.p. of water at 77^\circC and 27^\circC respectively are 314 mmHg and 27 mmHg. Treat the air in the vessel as an ideal gas] (c) The lengtn of a zinc rod at 23^\circC is 200 m. Calculate the increase in length of the rod when its temperature rises to 33^\circC. [ expansivity of zinc = 2.6 x 10\(^{-5}\) K\(^{-1}\)] (d) Explain with there is no temperature change when a solid being heated changes into liquid at its melting point.

(a) The equation y = \(\alpha\) sin (wt - kx) represents a plane wave travelling in a medium along the x-direction, being the displacement at the point x at time t. (i) Given that x is in metres and t is in seconds, state the units of k and w (ii) What physical quantity does \(\frac{W}{k}\) represent? Justify your answer (iii) State whether the wave is travelling in the positive or negative x-direction. (b)(i) What are beats? (ii) A sonometer wire has a frequency of 259 Hz. It is sounded alongside a tuning fork of frequency 256 Hz. Calculate the beat frequency (iii) The sonometer wire in (b)(ii) above is under a tension of 1200 N. If a metre of the wire has a mass of 0.03 kg, calculate the length l of the wire when it is vibrating in the fundamental mode. (c) List two similarities between the human eye and the photographic camera.

(a) What is a magnetic field? (b) With the aid of a labelled diagram describe an experiment to show that a magnetic field exists around a straight wire carrying current. (c) A 40 \(\mu\)F capacitor in series with a 40 Q resistor is connected to a 100 V, 50 Hz a.c. supply. (i) Draw a circuit diagram of the arrangement (ii) Calculate the: I. impedance in the circuit; II. current in the circuit III. potential difference across the capacitor.

(a)(i) State Einstein's equation of photoelectric effect (ii) What conservation principle does the equation represent? (b) List three applications of photocells (c) A photo emissive surface has a threshold frequency of 4.02 x 10\(^{14}\)Hz. If the surface is illuminated by light of frequency 5.0 x 10\(^{15}\)Hz, calculate the: (i) threshold wavelength; (ii) work function; (iii) kinetic energy of the emitted photoelectrons. [ c = 3.0 x 10\(^{8}\) ms\(^{-1}\), h = 6.63 x 10\(^{-34}\) Js]

You are provided with a uniform meter rule, a knife edge, masses and other necessary apparatus. Suspend the metre rule horizontally on the knife edge. Read and record the point of balance G of the métre rule. Keep the knife edge at this point throughout the experiment. Using the thread provided, suspend the object labelled W at the 15cm mark of the metre rule. Suspend a mass M= 20g on the other side of G. Adjust the position of the mass until the metre rule balances horizontally again. Read and record the position Y of the mass M on the metre rule. Determine and record the distance L between the mass and G. Also determine and record the distance D between W and G. Repeat the procedure for four other values of M = 30, 40, 50 and 60 g. In each casse ensure that W is kept Constant at the 15 cm mark and the knife edge at G. Evaluate L\(^{-1}\) in each case. Tabulate your readings. Plot a graph of M on the vertical axis against L\(^{-1}\) on the horizontal axis. Determine the slope S, of the graph. Evaluate \(\frac{4}{D}\) State two precautions taken to obtain accurate results. (b)i. State the principle of moments. ii. Define centre of gravity

Using the above diagram as a guide, carry out the following instructions. Fix a metre rule on the bench with its graduated side facing up. Place the illuminated object at the 0cm end and the screen at the 100cm end of the rule such that the distance d between the illuminated object and screen is 100cm. Record the distance d. Also, evaluate and record d\(^{2}\). Place and move the Converging lens between the illuminated object and the Screen until a sharp diminished image of the object is formed on the screen. Read and record the position Ih of the lens. Now move the lens towards the object until another sharp image of the object is formed on the Screen. Read and record the new position \(l_2\) of the lens. Evaluate and record L= (\(l_1\) - \(I_2\)), also evaluate L\(^{2}\) and D = d\(^{2}\) - L\(^{2}\). Repeat the procedure for four values of d= 85, 75, 65 and 55cm. Tabulate your readings. Plot a graph or Don the vertical axis against d on the horizontal axis. Determine the slope, s, of the graph. Evaluate k = \(\frac{s}{4}\). State two precautions taken to obtain accurate results. (b)i. Explain the statement the focal length of a converging lens is 15cm. ii. Distinguish between a real image and a virtual image.

You are provided with two resistance wires labeled A and B, a1\(\Omega\) standard resistor Rx, and other necessary apparatus. Connect \(R_x\) in the left-hand gap of the metre bridge, a length L= 100cm of wire A in the right-hand gap, and the other apparatus as shown in the diagram above. Determine and record the balance point P on the bridge wire NQ. Measure and record \(l_x\) = NP and \(l_y\) = PQ. Evaluate \(R_1\) = \(\frac{I_{y}}{L_{x}}\) = \(R_x\) Repeat the procedure for four other values of L= 95, 85, 75 and 65cm. In each case, determine and record the balance point P and the length \(l_x\) and \(l_y\). Also, evaluate \(R_1\). Repeat the experiment with the second wire B. Obtain the balance points P and the values of and \(l_x\) and \(l_y\). Evaluate \(R_1\) = \(\frac{I_{y}}{L_{x}}\) = \(R_x\) in each case. Tabulate your readings. Plot a graph of \(R_2\) on the vertical axis against \(R_1\) on the horizontal axis. Determine the slope, s, of the graph. Evaluate k = \(\sqrt s \). State two precautions taken to obtain accurate results. (b)i. State two advantages of using a potentiometer over a voltmeter for measuring the potential difference. ii. Define the internal resistance of a cell.

Chlorophyll obtained from green leaves of plant can be shown to be composed of more than one coloured component by the technique of

In countries where the temperature falls below 273K, salt is always sprinkled on the icy road in order to

2Na(s) + 2H2O(l) → 2NaOH(aq) + H2(g) From the equation above, calculate the mass of sodium hydroxide produced by 2.3g of sodium. [H = 1, O = 16, Na = 23]

16.8 g of sodium hydrogen trioxocarbonate (IV) is completely decomposed by heat. Calculate the volume of carbon(IV) oxide given off at s.t.p [Na 23, C = 12, O = 16, H = 1, Molar volume of a gas at s.t.p = 22.4 dm3]