(a) Define the following terms:

(i) Electric field intensity

(ii) Electric potential

(b) The diagram below illustrates two collinear electric charges of magnitudes + Q and -Q. The charges are equidistant from a point P at which a rest charge is placed.

Copy the diagram and use arrows to indicate, from the point P, the direction of the;

(i) electric force F\(_1\) due to + Q.

(ii) electric force F\(_2\) due to -Q.

(iii) electric field intensity E.

(c) What is meant by dielectric substance?

(ii) List the factors which determine the capacitance of a parallel plate capacitor and state the effect each of them has on the capacitance.The diagram above represents a section of a circuit. Calculate the effective capacitance in the section.

(iii)

The diagram above represents a section of a circuit. Calculate the effective capacitance in the section.

(a)(1) State the energy transformations which take place during the operation of a modern x-ray tube.
(ii) Distinguish between hard and soft x-rays.

(iii) State three uses of x-rays.

(iv) Mention one hazard of over-exposure to x-rays in a radiological laboratory, and indicate any two safety precautions.

(b) A possible fusion reaction is \(^2_1 H + ^2_1 H \to ^3_1H + ^1_1H + Q\)

where Q is the energy released as a result of the reaction. If Q = 4.03 MeV, calculate the atomic mass of \(^3_1H\) in atomic mass units. (\(^2_1 H = 2.01410 U; ^1_1H = 1.00783 U; 1U = 931 MeV\))

1. Using the spring balance provided, determine the weight of object of mass M = 5.0g. Record this weight as W\(_{1}\).
2. Determine the weight of the object when completely immersed in water contained in a beaker as shown in the diagram. Record the weight as W\(_{2}\)
3. Determine the weight of the object when it is completely immersed in the liquid labelled 'L'. Record the weight as W\(_{3}\). Evaluate, u = (W\(_{1}\) -W\(_{3}\)) and v = (W\(_{1}\) - W\(_{3}\)).
4. Repeat the procedure with the objects of masses M = 10, 15, 20, and 25g. In each case, evaluate u = (W\(_{1}\) - W\(_{3}\)) and v = (W\(_{1}\) - W\(_{3}\)) on the vertical axis against u = (W\(_{1}\) - W\(_{2}\) on the horizontal axis.
5. Determine the slope, s, of the graph. (vii) State two precautions taken to ensure accurate results.

(b)i. A piece of brass of mass 20.0g is hung on a spring balance from a rigid support and completely immersed in kerosine of density 8.0 x 10\(^{2}\)kg m\(^{-3}\). Determine the reading on the spring balance. [g= 10ms\(^{-2}\)], density of brass = 8.0 x 10\(^{3}\) kg m\(^{-3}\) J

ii. State Archimede's principle and the law of floatation.

1. Fix a metre rule on the bench with the graduated face up.
2. Place the illuminated object at the zero end of the rule and the screen at the other end as illustrated in the diagram above.
3. Measure and record D, the distance between the object and the screen. Evaluate D\(^{2}\).
4. Place and move the converging lens between the illuminated object and the screen until a diminished sharp image of the object is formed on the screen. Read and record the position, X\(_{1}\), of the lens. From this position, move the lens towards the object until another sharp image of the object is formed on the screen. Read and record the new position x\(_{2}\), of the lens.
5. Evaluate and record L (x\(_{1}\) - x\(_{2}\)), L\(^{2}\)) and (D\(^{2}\) - L\(^{2}\))
6. Repeat the procedure for D = 90, 80, 70 and 60 cm. In each case, evaluate, L L\(^{2}\) and (D\(^{2}\) - L\(^{2}\)). Tabulate your readings.
7. Plot a graph of D\(^{2}\) - L\(^{2}\) on the vertical axis against D on the horizontal axis.
8. Determine the slope, S, of the graph and evaluate K = \(\frac{s}{4}\). State two precautions taken to ensure accurate results.

(b)i. Distinguish between a real image and a virtual image.

Draw a ray diagram to show how a converging lens may be used to form a real diminished image of an object.

1. Measure and record the e.m.f. of the accumulator provided.
2. Connect a circuit as shown in the diagram. S is a standard resistor and R is a resistance box.
3. With R = 0\(\Omega\), close the key K. Read and record the ammeter reading I. Evaluate 1\(^{-1}\).
4. Repeat the procedure for R=1,2, 3, 4, and 5\(\Omega\). Tabulate your readings.
5. Plot a graph of R on the vertical axis and 1\(^{-1}\) on the horizontal axis, starting both axis from the origin (0,0).
6. Determine the slope s of the graph and find the intercept C on the vertical axis.
7. State two precautions taken to ensure accurate results.

(b)i. State two advantages of a lead-acid accumulator over a Leclanche cell.

ii. A parallel combination of 3\(\Omega\) and 4\(\Omega\) resistors is connected in series with a resistor of 4\(\Omega\) and a battery of negligible internal resistance. Calculate the effective resistance in the circuit.