Waec Physics 2000 Past Questions and Answers

Question 61:

• WAEC 2000

(a) Define angle of contact
(b) Draw sketches to show angles of contact for a capillary tube dipped vertically in (i) water; (ii) mercury.

Question 62:

• WAEC 2000

During the electrolysis of copper (II) tetraoxosulphate (VI) solution, a steady current of 4.0 x 10\(^2\) A flowing for one hour liberated 0.48 g of copper. Calculate the mass of copper liberated by one coulomb of charge.

Question 63:

• WAEC 2000

An electron of mass 9. 1 x 10\(^{-31}\) kg moves with a velocity of 4.2 x 10 ms\(^{-1}\) between the cathode and anode of an x-ray tube. Calculate the wavelength. (Take Planck's constant h = 6.6 x 10\(^{-34}\) J S)

Question 64:

• WAEC 2000

(a)(i) Define the term linear momentum.
(ii) State the law of conservation of linear momentum.
(b) A ball P of mass 0.25 kg, loses one-third of its velocity when it makes a head on collision with an identical ball Q at rest. After the collision, Q moves off with a speed of 2ms\(^{-1}\) in the original direction of P. Calculate the initial velocity of R
(c)(i) State Newton's second law of motion.
(ii) Show that F = ma where F is the magnitude of the force acting on a body of mass m to give it an acceleration of magnitude a.
(iii) The engine of a vehicle moves it forward with a force of 9600 N against a resistive force of 2200 N. If the mass of the vehicle is 3400 kg, calculate the acceleration produced.

Question 65:

• WAEC 2000

(a)(i) Mention two modes of heat transfer other than convection.
(ii) Explain land and sea breezes.
(b) An iron rod of length 30cm is heated through 50 kelvin. Calculate its increase in length. (linear expansivity of iron = 1.2 x 10\(^{-5}\)K\(^{-1}\)
(c) An electric heater immersed in some water raises the temperature of the water from 40°C to 100°C in 6 minutes. After another 25 minutes, it is noticed that half the water has boiled away. Neglecting heat losses to the surrounding, calculate the specific latent heat of vaporisation of water.