Physics JAMB, WAEC, NECO AND NABTEB Official Past Questions

You are provided with a potentiometer x y; a jockey, J; a standard resistor, R, and other necessary apparatus.

1. Connect a circuit as shown in the diagram above.
2. Close the key. Read and record the current 10 when J is not in contact with XY.
3. Let J make contact with XY at C, such that XC = l= 25 cm. Close the key. Read and record the current l.
4. Evaluate I\(^{-1}\).
5. Repeat the procedure for four other values of I = 40, 55, 70, and 85 cm. Tabulate your readings.
6. Plot a graph of l on the vertical axis against I\(^{-1}\) on the horizontal axis.
7. From your graph, deduce the value of I when l\(^{-1}\) = 0. Evaluate \(\frac{|O}{1}\)
8. 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. A piece of resistance wire of diameter 0.2m and resistance 7\(\Omega\) has a resistivity of 8.8 x 10\(^{-7}\) \(\Omega\)m. Calculate the length of the wire. [\(\pi\) = \(\frac{22}{7}\)].

Using the diagram above as a guide, carry out the following instructions:

1. Fix. the drawing paper provided on the drawing board
2. Place the mirror vertically with its longer side resting on the drawing paper. Trace the outline AB of the mirror. Remove the mirror.
3. Draw a normal PQ to meet the outline at the middle Q.
4. Draw a straight line through A to meet the outline of the mirror at the right angle.
5. Trace the incident ray, Q with pins P\(_{1}\) and P\(_{2}\) so that it meets the perpendicular line through A at C such that CA=X= 1.0m.
6. Replace the mirror on its outline. Locate the images of P\(_{1}\)P\(_{2}\) through the mirror using two other pins P\(_{3}\) and P\(_{4}\) so that P\(_{3}\) and P\(_{4}\) and the images of P\(_{1}\) and P\(_{2}\) are in a straight line.
7. Remove the mirror and pins P\(_{3}\) and P\(_{4}\).
   Draw a straight line through the pin points to meet AB at Q and CA produced at D.
8. Measure and record angle ACQ as è\(_{1}\), and angle ADCQ as è\(_{2}\). Also, record the value of x. Evaluate è = (è\(_{1}\) + è\(_{2}\)), x\(^{-1}\) and tan è.
9. Repeat the procedure for four other values of x = 2.0, 3.0, 4.0 and 5.0cm. Tabulate your readings.
10. Plot a graph of tan è on the vertical axis against x on the horizontal axis.
11. Determine the slope, s, of the graph. Evaluate k = 2s
12. State two precautions taken to ensure accurate results. Attach your traces to your answer booklet.

(b)i. Distinguish between regular and diffused reflections.

ii. An object is situated 25cm in front of a plane mirror. Determine the distance of the image from the object. What is the size of the image relative to the object?

You are provided with a metre rule, a knife edge, two pieces of thread and two masses m\(_{1}\) and m\(_{2}\)

1. Record the values of m\(_{1}\) and m\(_{2}\).
2. Balance the metre rule horizontally on the knife edge and record the balance point G.
3. With the knife edge at the 60 cm mark of the metre rule, suspend m\(_{1}\) at the 20 cm mark and m\(_{2}\) at a suitable mark such that the rule balances horizontally as illustrated in the diagram above.
4. Record the positions Y of m\(_{1}\) and Q of m\(_{2}\). 
5. Evaluate 1= P – Y and d = Q – P
6. Repeat the procedure for four other positions of m, at 18, 16, 14 and 12 cm marks.
7. In each case, evaluate and record l and d.
8. Tabulate your readings.
9. Plot a graph of l on the vertical axis against d on the horizontal axis.
10. Determine the slope of the graph.
11. State two precautions taken to ensure accurate results.

(b}i. With the aid of a diagram, indicate the forces acting on the metre rule in the experimental set-up above.

ii. Define moment of a force about a point and state its S.1. unit.

(a)(i) Explain photoelectric emission.

(ii) State four applications of photoelectric emission.

(b) Draw and label a diagram showing the structure of a simple type of a photocell and explain its mode of operation.

(c) In a photocell, no electrons are emitted until the threshold frequency of light is reached.

(i) Explain what happens to the energy of the light before emission of electrons begin.

(ii) State one factor that may affect the number of emitted electrons.

(a)(i) What is meant by neutral point in a magnetic field?

(ii) Draw and label a diagram to show the pattern and direction of the magnetic field produced around a straight current-carrying wire.

(b) When is an ammeter said to be (i) Sensitive (ii) accurate?

(c)(i) Explain, using a labelled diagram, how a delicate magnetic material could be protected, from the Earth’s magnetic field.

(ii) A charge of 1.6 x 10\(^{-19}\) C enters a magnetic field of flux density 2.0 T with a velocity of 2.5 x 10\(^7\) ms\(^{-1}\) at an angle of 30° with the field. Calculate the magnitude of the force exerted on the charge by the field.

(d) State the laws of electro-magnetic induction.

a) (i) Illustrate, using a ray diagram, how an image can be formed by a convex mirror.

(ii) State one advantage rid one disadvantage of using a convex mirror as a iving mirror.

(iii) Explain the action of a compound microscope.

(b) Illustrate using labelled diagrams only, sonometer wire of length I, vibrating at its fundamental (ii) first overtone (iii) second overtone

(c) A tuning fork vibrating at a frequency of 512 Hz is held over the top of a jar filled with water and fitted with a tap at the buttom. If the jar is 60 cm tall and the speed of sound is 350 ms\(^{-1}\), determine the possible resonance position(s).

(a) Using the kinetic theory of matter, explain why; 

(i) Evaporation causes cooling

(ii) Boiling water changes to steam without any change in temperature, although heat is being supplied to the water.

(b) (i) State Boyle’s law.

(ii) With the aid of a labelled diagram, describe an experiment to illustrate the relationship between the volume and pressure of a given mass of gas at constant temperature. (iii) State two precautions necessary to obtain accurate results.

(a) Define (i) Linear momentum; (ii) Impulse

(b) State the principle of conservation of linear momentum.

(c) A tractor of mass 5.0 x 10\(^{3}\)kg is used a tow a car of mass 2.5 x 103 kg. The tractor moved with a speed of 3.0 ms\(^{-1}\) just before the towing rope becomes taut. Calculate the:

(i) Speed of the tractor immediately the rope becomes taut

(ii) Loss in kinetic energy of the system just after the car has started Moving;

(iii) Impulse in the rope when it jerks the car into motion.

(a) What is meant by the wave-particles duality of matter?

(b) mention one physical phenomenon, in each case, that can be explained in terms of the wave nature and particle nature of light.

A force of 40 N applied at the end of a wire of length 4m and diameter 2.00 mm produces an extension of 0.24 mm. Calculate the;

(a) stress on the wire;

(b) strain in the wire (\(\pi = 3.142\))

Define;

(i) Elasticity

(ii) Young’s modulus

(iii) Force constant

(a) What is the principle upon which the lighting in fluorescent tubes operate?

(b) State two factors which determine the colour of projection, g the acceleration of free fall due to gravity light from a fluorescent tube

(a) Explain the term electrolyte and give two examples.

(b) State the relationship between the mass of a substance liberated during electrolysis and the charge passed.

Explain the rise of water in a glass capillary tube using the kinetic theory.

(a) List two types of waves, apart from light, that can be plane polarized.

(b) State two applications of plane polarized light.

(a) Explain diffusion

(b) State one factor that can affect the rate of diffusion.

(a) What is surface tension?

(b) State two methods by which the surface tension of a liquid can be reduced.

(a) State two objects each used in sports and warfare which may be considered as projectiles. 

(b) the horizontal range R, of a projectile is given by the expression;

R = \(\frac{u^2 sin 2\theta}{g}\) where \(\theta\) is the angle of projection, g the acceleration of free fall due to gravity and u the initial velocity. At what value of \(\theta\) will R be maximium?

The bar magnet illustrated in the diagram above picks up an unmagnetised steel nail X. In turn, X picks up a similar nail Y and so on. The nail are said to be magnetised by

The diagram above shows the resultant electric field pattern due to two electric point charges P and S. Which of the following statements is correct?

Which of the following reactions represents nuclear fusion?