Measure and record the e.m.f of the accumulator provided. Connect the circuit as shown in the diagram. With zero resistance in the resistance box, adjust the rheostat to obtain the maximum possible reading on the ammeter. Do not adjust the rheostat again throughout the experiment. Open the key. With R= 1\(\Omega\), close the key, read and record the reading of the ammeter I. Calculate 1\(^{-1}\) Repeat the experiment for R=2,3,4 and 5\(\Omega\) respectively. In each case, read and record the value of 1\(_{A}\) and calculate the Corresponding value of l\(_{A}^{-1}\). Now connect the resistor Q in series into the circuit and without altering the setting of the rheostat, record the new ammeter readings l\(_{B}\) for R= 1,2,3, 4, and 5\(\Omega\). Calculate the corresponding value of l\(_{B}\) in each case. Tabulate all your readings. On the same graph and using the same axes and scales, plot the graphs of:
(i) I\(_{A}^{-1}\)’ on the vertical axis and R on the horizontal axis;
(ii) l\(_{B}^{-1}\) on the vertical axis and R on the horizontal axis. Calculate the slopes S\(_{A}\) in (i) and S\(_{B}\) in (ii) above. Determine the difference D between the intercepts of the graphs on the vertical axis. State two precautions taken to ensure accurate results.
(b) i. Explain why a battery of eight dry Leclanche cells, each of e.m.f. 1.5v is not normally used in place of a motor-car battery of 12V to start a car.
ii. State two sources of e.m.f. other than the chemical cell.
Trace the outline ABCD of the glass block on the sheet of paper as shown in the diagram. Remove the block and draw the normal at O. Draw an incident ray such that the angle of incidence i =30°. Fix two pins at points P and Q on the incident ray. Replace the block and fix two other pins at points U and V such that the pins appear to be in a straight line with the images of the pins at P and Q when viewed through the block. Remove the block and join the points at V and U, producing the line to meet DC at T. Join OT With O as a center and using any convenient radius, draw a circle to cut the incident and refracted rays at R and S respectively. Draw the perpendiculars RN and MS. Measure and record RN and MS. Repeat the experiment for i = 40° 50° 60° and 70° respectively. In each case, determine and record the corresponding values of RN and MS. Tabulate your readings. Plot a graph of RN on the vertical axis and MS on the horizontal axis. Determine the slope s of the graph, State two precautions taken to ensure accurate results. [Attach your traces to your answer script]
(b)i. Explain refraction.
ii. Draw a diagram showing why a metre rule, partly immersed in water and placed obliquely to the surface appears bent at the surface.
In the diagram, a thread AC, fixed at pulley A passes over pulley C on a force board and carries an unknown mass m\(_{o}\). Retain this mass m\(_{o}\) throughout the experiment. Draw a line along the direction of AC on the paper held behind the thread. Locate the mid-point B of AC and mark its position on this line. Draw BP at right angles to AC. By means of a loop of thread, suspend a mass M 50 g from AC and adjust the position of the loop so that the line of action of the weight of M lies along with BP. Ensure that M and m\(_{o}\), hang off the force board. Measure BO = y and AO. Evaluate y / AO. Repeat the experiment for M = 70,90,110 and 130g respectively. In each case, determine the corresponding values of y, AO, and y / AO. Tabulate your readings. Plot a graph of Y/AO on the vertical axis and M on the horizontal axis. Determine the slopes s of the graph. State two precautions taken to ensure accurate results. Attach your traces to your answer script.
(b)i. Distinguish between the resultant and the equilibrant of forces.
ii. State two conditions necessary for the equilibrium of three non-parallel coplanar forces.
(a) Explain: (i) Fusion. (ii) Fission.
(b) State three advantages of fusion over fission in the generation of power
(c) Calculate in joules, the binding energy for
\(\frac{59}{27}\) Co
(Atomic mass of \(^{59}_{2} Co\) = 58.9332 u)
(Mass of proton = 1.00783u)
(Mass of neutron = 1.00867 u)
(Unified atomic mass unit, U = 931 MeV)
(1 eV = 1.6 x 10\(^{-19}\) J)
(a) Sketch the magnetic flux pattern around a long; straight, current-carrying wire
(b) State two methods by which the sensitivity of a moving-coil galvanometer can be increased.
(c) A series RLC circuit comprises a 100-\(\Omega\) resistor, a 3-H inductor and a 4-\(\mu\)f capacitor. The a.c source of tile circuit has an e.m.f of 100V and a frequency of 160 Hz.
(i) Draw the circuit diagram of the arrangement. Calculate the:
(ii) capacitive reactance;
(iii) inductive reactance:
(iv) impedance of the circuit;
(v) current in the circuit;
(vi) average power dissipated in the circuit.
(a) State three properties of waves
(b)(i) Describe, with the aid of a labelled diagram, an experiment to show how the frequency of the note emitted by a vibrating string depends on the tension in the string
(ii) State two precautions necessary to ensure accurate results.
(c) Draw a ray diagram showing how a virtual image of an object is formed by a concave mirror.
(a) Explain (i) work: (ii) power
(b) Show that the efficiency E, the force ratio M.A. and the velocity ratio V.R. of a machine are related by the equation: E = M.A. x 100% V.R.
(c) An inclined plane of angle 15° is used raise a load of 4500N through a height of 2m. If the plane is 75% efficient calculate:
(i) velocity ratio of the plane;
(ii) work done on the load
(d) Explain Charles’ law using the Kinetic theory of matter.
(a) State the conditions for the equilibrium of a rigid body acted upon by parallel forces
(b)(i) Describe an experiment, using the principle of moments, to determine the mass of a metre rule
(ii) State two precautions necessary to ensure accurate results.
(c) A bullet of mass 120g is fired horizontally into a fixed wooden block with a speed of 20ms\(^{-1}\). 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.
(a) State Heisenberg’s uncertainty principle.
(b) Mention two phenomena that can only be explained in terms of the particulate nature of light.
(a) Explain electrolysis
(b) Classify the following substances as electrolytes and non-electrolytes: Sugar solution: paraffin, suit solution and grape fruit juice.
(a) State Hooke’s law of elasticity
(b) A spiral spring, loaded with a piece of metal, extends by 10.5cm hair. When the metal is fully submerged in water, the spring extends by 6.8cm. Calculate the relative density of the metal. (Assume Hooke’s law is obeyed).
(a) List two types of waves, apart from light, that can be plane polarised
(b) State two applications of plane polarised light.
(a) What is the principle upon which the lighting in fluorescent tubes operate?
(b) State two factors on which the colour of light from a fluorescent tube depends.
(a) Define Young’s modulus.
(b) State the physical quantities one has to measure in order to determine the Young’s modulus of a wire.
(a) What is surface tension?
(b) State two methods by which the surface tension of a liquid can be reduced.
In an electrolysis experiment, the ammeter records a steady current of 1A. The mass of copper deposited is 0.66g in 30 minutes. Calculate the error in the ammeter reading (Electrochemical equivalent of copper = 0.00033g C\(^{-1}\)).
A stone is projected horizontally from the top of a tower with a speed of 5ms-1. It lands on the ground level at a horizontal distance of 20m from the foot of the tower. Calculate the height of the tower. (g = 10ms\(^{-2}\))
Which of the following is not a safety precaution in a nuclear station?
- A. Radioactive materials are stored in glass casings
- B. Radioactive materials are handled with remote-controlled tongs
- C. Technicians in nuclear stations wear radio-sensitive badges which are checked regularly.
- D. Radioactive materials are kept in thick-walled lead containers
Which of the following are the essential parts of an atomic bomb?
- A. Uranium and neutrons
- B. Radium and polonium
- C. Nitrogen and neutrons
- D. ranium and α - particles.
A sheet of paper is placed in the path of the following radiations: I. Alpha particles II. Beta particles III. Gamma rays. Which of the radiations will pass through the sheet of paper?
- A. I only
- B. II only
- C. I and II only
- D. II and III only