Physics JAMB, WAEC, NECO AND NABTEB Official Past Questions

A photon of wavelength 6.0 x 10\(^{-7}\) m behaves like a particle of a certain mass. The value of that mass is [h = 6.63 x 10\(^{-34}\) Js, c = 3.0 x 10\(^8\) ms\(^{-1}\)]

(a) You are provided with two metre rules, two retort stands, a mass, m = 100g, thread, and other necessary apparatus

(i) Place one of the metre rules on a knife edge and determine the centre of gravity, C

(ii) Measure and record the mass, M\(_R\) of the metre rule

(iii) Attach the mass = 100g firmly to the metre rule AB at C using paper tape

(iv) Suspend the metre rule by two parallel threads of length, h = 40cm each at 10 cm and 90cm mark. Ensure that the graduated face of the metre rule is facing upwards.

(v) Set the metre rule into small angular oscillation about the vertical axis through the centre of gravity.

(vi) Determine the time, t for 20 complete oscillations. Evaluate the period T and T\(^2\).

(vii) Read and record the value of d in metres.

(viii) Keeping d, constant, repeat the procedure for four other values of h = 50, 60, 70, and 80 cm. In each case, determine t and evaluate T and T\(^2\).

(ix) Tabulate the readings 

(x) Plot a graph of T\(^2\) on the vertical axis and h on the horizontal.

(xi) Determine the slope, s of the graph

(xii) Evaluate K = \(\frac{\text{S}}{\text{Q}}\) where Q = \(\frac{2}{25d^2}\)

(xiii) State two precautions taken to ensure accurate results

b(i) Define couple as it relates to oscillatory motion

(ii) Give two practical applications of a couple in everyday life.

                                                                                 ALTERNATIVE B

(a) You are provided with a variable DC power supply E, a key, an ammeter, a voltmeter and other necessary materials

(i) Set up a circuit as shown in the diagram above with E = 3.0V

(ii) Close the key.

(iii) Record the voltmeter reading, V

(iv) Read the corresponding ammeter reading, I

(v) Evaluate V\(^{-1}\) and I\(^{-1}\)

(vi) Repeat the procedure for the four other values of E = 4.5V, 6.0V, 7.5V and 9.0V.

(vii) Tabulate your readings.

(viii) Plot a graph with I\(^{-1}\) on the vertical axis and V\(^{-1}\) on the horizontal axis starting with both axes from the origin. (0, 0)

(ix) Determine the slope, s of the graph.

(x) Also, determine the intercept, c on the vertical axis

(xi) What does the slope, s represent?

(xii) State two precautions taken to ensure accurate results.

(b) State two methods by which an electric current can be produced

(i) State Ohm’s law.

(a) You are provided with two resistance wires labelled: A and B, standard resistor, R\(_x\) = 1 \(\Omega\), metre bridge, cell of emf,E, Rheostat  R\(_h\), galvanometer and apparatus as shown.

Use the circuit diagram above as a guide to perform the experiment.

(i) Connect  R\(_x\) in the left-hand gap of the metre bridge, a length L = 100 cm of the wire in the right-hand gap and the other apparatus shown.

(ii) Determine and record the balance point P on the metre bridge wire NQ

(iii) Measure and record L\(_x\) = NP and L\(_y\) = PQ

(iv) Evaluate R\(_1\) = \(\frac{L_y}{L_x}R_x\)

(v) Repeat the procedure for four other values of L = 90cm, 80cm, 70cm, and 60cm. In each case, determine and record the balance point, P and evaluate R\(_1\)

(vi) Repeat the experiment with the second wire B. Obtain the balance point P and evaluate R\(_2\) in each case

(vii) Tabulate the readings

(viii) Plot a graph of R\(_2\) on the vertical axis and R\(_1\) on the horizontal axis

(ix) Determine the slope, s, of the graph

(x) Evaluate K = \(\sqrt{s}\)

(xi) State two precautions taken to ensure accurate results.

b(i) State two advantages of potentiometer over voltmeter for measuring potential difference

(ii) Define internal resistance of a cell.

(a) You are provided a retort stand, a spring balance, masses, a beaker containing water, another beaker containing a liquid labelled, L, and other necessary apparatus.

(i) Suspend the mass, m = 20 g on the spring balance and measure the weight in air, W\(_A\) in Newton.

(ii) Immerse the suspended mass completely in water and measure weight in water, W\(_W\) in Newton. Evaluate U\(_1\) = W\(_A\) – W\(_W\).

(iii) Immerse the suspended mass completely in the liquid L of the same volume with water and measure the weight in liquid W\(_L\). Evaluate U\(_2\) = W\(_A\) – W\(_L\).

(iv) Repeat the procedure for m = 40g, 60g, 80g, and 100g respectively. In each case, evaluate \(W_A\), W\(_W\), U\(_1\), W\(_L\), U\(_2\).

(v) Tabulate the readings.

(vi) Plot a graph of U\(_1\) on the vertical axis and U\(_2\) on the horizontal axis starting both axes from the origin (0, 0).

(vii) Determine the slope s of the graph

(viii) Evaluate K = \(\frac{1}{\text{s}}\)

(ix) State two precautions taken to ensure accurate results.

b(i) State the Archimedes’ principle,

(ii) State two differences between density and relative density

(a) Mention three facts about photoelectric effect

(b) An electric magnetic radiation source of power 6 x 10\(^{-3}\) W emits 1 x 10\(^{16}\) photons per second. The most energetic photo electron ejected from a metal surface is stopped by a potential difference of 2.2V. Calculate the work function of the metal. [ mass of (photon) electrons 9.1 x 10\(^{-31}\) kg, e = 1.6 x 10\(^{-19}\) C]

(c) State two factors on which the activity of a radioactive sample depends

(d) Cobalt-60 source has an activity of 2.0 x 10\(^6\) Bq and a half-life of 1.8 x 10\(^8\)s. Calculate the number of radioisotope nuclei in the source.

(a)i State the condition for a charged particle to experience a force in magnetic field

(ii) State the expression for the magnetic force, F acting on a charged particle, Q in a magnetic field of flux density, \(\beta\) with speed, V

(iii) Prove quantitatively that there is no magnetic force moving along the direction of a magnetic field.

(b)i Mention the main parts of an electrical transformer.

(ii) Explain how an alternating potential difference applied to the primary coil gives rise to an induced e.m.f in the secondary coil of a transformer.

(c) Proton of mass 1.7 x 10(^{-27}\) kg enters a magnetic field of flux density 0.207 normally and followed a quarter circle path before existing with a constant speed of 4.5 x 10\(^6\)m/s

(i) Explain why the speed of the proton remains constant.

(ii) Calculate the 

I. radius of the circular path

II. time taken by the proton to move through the magnetic field [e = 1.6 x 10\(^{-19}\) C, \(\pi\) = 3.14]

(a) State the condition for light ray incident on a concave mirror to reflect through the principal focus of the mirror.

(b) Explain spherical aberration as a defect of curved mirrors

(c) The diagram above illustrates an image formed when an object is placed in front of a particular lens. Redraw the diagram and indicate the center of curvature, C, principal focus, F, and the principal axis. ( SEE THE DIAGRAM ABOVE)

(d) What is meant by accommodation in connection to the human?

(e) State quantitatively, the (i) values of the near and far point of a normal eye. (ii) Use the answer in 10c(i) to determine the change in optical power of the normal human eye when reading a book and viewing the sky.[lens-to-retina distance = 2.5 cm].

(a)(i) What is a thermometric liquid?

(ii) State the reason for the following design features of a clinical thermometer. I. Narrow bore: II. Thin wall of the bulb 

(b) Distinguish between heat and temperature of an object in terms of the energy of a particle

(c) Explain why evaporation leads to cooling

(d) A kettle rated 2000W, contains water at 20ºC. The kettle is switched on and after two minutes, the water starts boiling. After another six minutes, 45% of the water in the kettle boils away. (i) Determine the specific latent heat of the vaporization of the water (ii) State one assumption made in your calculation 9d(i) above

                                                   PART2

(a) State the effect of increasing temperature on the viscosity of a: (i) liquid, (ii) gas

(b) State two factors that determine the magnitude of a moment of a force

(c) A uniform stick AB of length, L, and mass, m, is balanced horizontally on a knife edge 10.0cm from A when an object of 400 g is suspended at A. When the knife edge is moved 5 cm further, the object has to be moved to a point 9.00 cm from A for the stick to balance.

(i) Represent the balance system with a suitable diagram

(ii) Determine the: I. mass, m of the stick; II. length, L.

(d) Explain in terms of air molecules why pressure at the top of a high mountain is less than at sea level.

(e) Mercury of density 13.6 x 10\(^3\)kgm\(^{-3}\) is poured in a container of uniform cross-sectional area 40cm \(^2\) to a height of 20 cm. The total pressure exerted on the base of the container is 1.42 x 10\(^5\)P. Calculate the: (i)  mass of the mercury in the container and (ii) pressure exerted at the surface of the mercury. [g = 10ms\(^{-2}\)

The fractional change in length produced in an elastic material of spring constant 680Nm\(^{-1}\) when a force of 306N is applied to stretch it is 1.5. Calculate the original length of the material.

An electron of mass, m, and charge, e moves through the electric field of potential difference V\(_o\) with a speed, v. Show that de Broglie wavelength associated with the electron is given as \(\lambda\) = \(\frac{\text{h}}{\sqrt{2meV_o}}\), where h is the Plank’s constant.

State three uses of ferromagnetic materials

An object projected at an angle to a ground level has a time of flight 4 seconds to move through still air. Calculate the maximum height attained by the object.[g = 10ms\(^{-2}\)]

(a) State the S.I  base unit of the following quantities: (i) a stress, (ii) force constant (iii) Plank’s constant

(a) State two uses of a polar satellite.

(b) What does the slope of a graph of tensile stress against tensile strain represent?

(a) Derive the dimension of surface tension.

(b) Name the instrument used to measure the force of gravity at a place

The diagram above illustrates the graph for 

The constant temperature at which a liquid change into gaseous state is known as 

Water is readily available but it is not a thermometric liquid mainly because 

The amount of heat energy that will be extracted when 0.02kg of water vapor condenses to water at 97ºC is [specific heat capacity of water = 4200Jkg\(^{-1}\)k\(^{-1}\), Specific heat of vaporization of water = 2.26 x 10\(^6\)Jkg\(^{-1}\)]