WAEC Physics 1999 Past Questions

Explain plane polarisation of light

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\(^{-2}\))

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) What is surface tension?

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

(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 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) List two types of waves, apart from light, that can be plane polarised

(b) State two applications of plane polarised light.

(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) Explain electrolysis

(b) Classify the following substances as electrolytes and non-electrolytes: Sugar solution: paraffin, suit solution and grape fruit juice.

(a) State Heisenberg's uncertainty principle.

(b) Mention two phenomena that can only be explained in terms of the particulate nature of light.

(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) 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 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) 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) 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)