# CONFIRM 2012 WAEC PHYSICS QUESTIONS AND ANSWERS

Filed in Uncategorized by on May 7, 2012

OBJ:

1-10 DABACDDBCA

11-20 BCDCCBBCDA

41-50 DCBACDCCBD

(2) relative density(10.5cm)/(6.8cm) =1.544. (8a) on the principle that gases give out light (glows) when electricity passes through them at low pressure and high voltage.

(8b)*magnivde of the voltage *the distance of seperation between the anode and the cathode

(6a) surface tension is a phenomenum by which the surface of a liquid behaves as if it were coverd by an elastic skin.

(6b) * by boiling, * dissolution of camphor

(4a) Electrodes are the negative plates in electric cell. The positive plate is the anode which the negative plates is the cathode.

(4b) formular,m= z it 200=8.33* 0.0001*I *1*120, I=200/120*8.33*0.0001, I=2000.8A

QUESTIONS

2]A spiral with a metal extends ay 10.5cm in air, when d metal is fully Submerged in water, d spring extends by 6.8cm. Calculate the relative density of the metal.(Assume Hooke’s Law is Obeyed)

3]A ray of light is incident on an air-glass boundary at an angle t, if the angle btw the Partially reflected ray and d refacted ray is 90degree, cal O, given that the Refractive index of glass is 1.50.

4]a)Explain the term electrodes in electric oclls.

b)An electric current passin tru an electrolyte for 2 minutes deposited 200g of a substance.If the Electrochemical Equivalent of the substances is 8.33 X 10^-4gc^-1. Calculate the current Passed.

5]Explain why sound waves cannot be Plane polarized.

6]a)Define surface tension.

b] State 2 method by which d surface tension of a Liquid can be reduced.

7]Explain why it’s desirable to invail an air conditionfr near the ceilling of aroom and not close to the floor.

8]a)on wat principle does lighting in a fluorescent tube operate?

b]state 2 factors which determine d colour of light produced in a fluorescent tube.

15ai]Explain why X-rays can be used to Produce Photographs of Fractures in Bones. ii]List 4 Uses of X-rays other than in Medicine.

b]State the energy Transformations which takes Place during the Operation of an X-ray tube.

ci]Explain three named dangers to which human beings may be exposed when Subjected to Large doses of X-rays.

ii]State two Precautions that must be taken by Persons working with X-rays.

d]In an X-ray tube, an electron is accelerated from rest towards a tungsten target biased at a Potentialof 33kv.

Calculate, for the Electron, the…

i]Kinetic Energy;

ii]Velocity.

[h=6.6 X 10^-34 js; Me=9.1 X 10^31kg; C=3.0 X 10^-8 ms^-1; e=1.6