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.

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.

You are provided with a uniform metre rule, a knife edge and a body m of mass 50g. Suspend the given body m by means of a thread from 1.0cm mark of the metre rule. Balance the loaded metre rule on the knife-edge as shown in the diagram above. Determine and record the value of x when the metre rule is in horizontal equilibrium. Evaluate \(\frac{1}{x}\). Repeat the experiment for values of m = 70, 90, 110, 130 and 150g respectively. In each case, determine and record the corresponding values of x and \(\frac{1}{x}\). Tabulate your readings. Plot a graph of m on the vertical axis and \(\frac{1}{x}\) on the horizontal axis, starting both axes from the origin (0,0). Determine the slope s, of the graph and the value of m for which /\(\frac{1}{x}\) = 0. State two precautions taken to ensure accurate results.

(b)i. Using your graph, determine the value of x for which m = 0.

(ii) State two conditions necessary to maintain the metre rule in the experiment above, in equilibrium.

(iii) Using your graph, determine the value of x for which m = 100g.

Trace the outline PQRS of the glass block on a sheet of paper, as shown in the diagram. Remove the block Mark a position 0 very close to P. Draw the normal NOG From point G, measure and mark out Points B\(_{1}\) B\(_{2}\) B\(_{3}\) B\(_{4}\) and B\(_{5}\) along with line GR at distances 1, 2, 3, 4 and 5cm respectively from G. Replace the glass block on the outline PORS Erect a pin at 0 and another at B\(_{1}\). Now fx a pin at T\(_{1}\) such that the pins at T\(_{1}\) and B\(_{1}\) are in line with the pin at O when viewed through the side SR of the glass block. Remove the glass block. Join the line OB\(_{1}\) and B\(_{1}\)T\(_{1}\). Measure and record the angles x and y. Evaluate sin x and y. Repeat the experiment with the pin at B\(_{1}\) fixed at B\(_{2}\), B\(_{3}\), B\(_{4}\) and B\(_{5}\) respectively while the pin at O remains unaltered. In each case, measure and record the values of x, y, sin x, and cos y. Tabulate your readings. Plot a graph of sin x on the vertical axis and cos y on the horizontal.axis, starting both axes from the origin (0,0). Calculate the slope, s of the graph. Evaluate K= \(\frac{1}{s}\). State two precautions taken to ensure accurate results. [Attach your tracings to your answer booklet]

(b)i. State Snell's law of refraction and explain why reaction Occurs at the boundary between two media.

ii. Differentiate refraction from diffraction.

iii. State two conditions necessary for total internal reflection to occur in a medium.

Connect the circuit as shown above. Set the value of R= 30\(\Omega\). Close the key and obtain a balance at point T on the potentiometer wire PQ. Read and record the length TQ = L Evaluate L\(^{-1}\) and R\(^{-1}\), Repeat the experiment for R= 20, 10.5, 3 and 1\(\Omega\) respectively. In each case, determine and record the corresponding values of LL\(^{-1}\) and R\(^{-1}\). Remove the resistance box from the circuit and then determine the length L\(_{o}\) corresponding to R= 0. Tabulate your readings. Plot a graph at R\(_{1}\) on the vertical axis, and L\(^{-1}\) on the horizontal axis, starting both axes from the origin (0,0). Determine the slope, s of the graph and its intercept, I on the vertical axis.
Evaluate: (i) k = 1\(^{-1}\)
                (ii) \(\frac{Lo}{S}\)
State two precautions taken to ensure accurate result

(b)i. Using your graph, determine the value of L for which R =15\(\Omega\).

ii. if the intercept I = 0.5+ y\(^{-1}\), use your graph to determine the value of y.

iii. Explain what is meant by the e.m.f.of a cell.