Thursday, September 19, 2013

FET Examinations and Answers

786 FET Examination Questions and Answers

Nature: Physics

1. List the core steps of the scientific method.
Answer: Identify what, Predict result (hypothesis), Design Experiment, Determine Control elements (unchanging ones) and variable (changing ones), Collect data, Interpret, Verify results, Explore Findings, Formulate the Pattern of events, Write the Law of the Result. 

2.  Choose from the words below to fit the sentences/ statements:
Amplitude, Velocity, Period, Speed.
a. The number of meters travelled per second...
b. the Maximum vertical distance a wave rises or drops from the equilibrium position
c. The pace at which a wave moves per second is called ....
d. the time a wave takes to pass a given point.
Answer: a) Velocity. b) Amplitude. c) Speed. d) Period. 

3. Which apparatus will represent electrolysis?
Answer: Two rods in an Electrolyte solution with a current attached to it

4. Give the name of CuCl2 and as what will it function?
Answer: Copper Chloride, functions as an ionic electrolyte that will allow ions to freely flow when the current is switched on.

5. Why are Carbon Electrodes used when CuCl2 is the electrolyte?
Answer: Carbon does not have an affinity (attraction/ reaction) with Copper/ Chorine

6. What is Electrolysis?
Answer: The process in which electric current is used to separate ionic compounds

7. Give the Chemical Equation of the reaction caused by the current sent through a CuCl2 solution.
CuCl2 -> Cu++  + Cl--

8. Explain why the Cu-deposit settles onto the Cathode (- Charged Electrode) and the Cl2 gas bubbles at the Anode(+ Charged Electrode)
Answer: The Cu -ions are positively charged and is therefore attracted to the Cathode (- electrode). This is the brown deposit on the negative electrode. The Cl2 gas are negatively charged ions that are attracted to the + Charged electron (anode), hence/therefore the bubbles at the positive electrode.

9. Match Column Numbers and B Letters                               
1. Vacuum
A. Light Bending
2. Displacement
B. rear-view mirror
3. Refraction
C. waves bend at ends
4. Reflection                                    
D. Space with no air molecules
5. Concave Mirror                            
E. higher wave
6. Convex Mirror                              
F. Direction
7. Super Position                              
G. Shaving
8. Diffraction                                    
H. Straight-line distance
9. Vector                                          
I.  no direction
10. Scaler                                          
J. light ray bounces off at 90 degrees

Answers: 1-D; 2-H; 3-A; 4-J; 5-G; 6-B; 7-E; 8-C; 9-F; 10-I. 

10. In reaction 2H2 + 02 ->  2H20
a. Give the names of the reactants
b. How many moles of reactants yield how many moles of the product
c. Give the Molar ratio of the above reaction

a. Hydrogen, Oxygen. 
b. Water
c. 2moles of Hydrogen, 1mole of Oxygen yield 2moles of Water
d. 2:1:2

11. The electron in a hydrogen atom is on average 5x10 to power minus 11 meters from the proton in the nucleus of the atom. Calculate the Electrostatic Force (F) of attraction between a proton and an electron separated by 5 x 10 to power minus 11. (K= 9 x 10 to the power plus 9; Proton Charge = Electron Charge = 1,6 x 10 to the power minus 19; F=K Qq/r squared)


F = K Qq/r squared
   = 9 x 10 to the power 9 x 1,6 x 10 to the power minus 19 x 1,6 x 10 to the power minus 19 DIVIDE by 5 x 10 to the power minus 11 squared
   = 9,216 x 10 to the power minus 8 Newton

12. Two athletes R and L compete in a 100m event. R accelerates uniformly @ 2m/s from his starting block for 4 seconds to reach his maximum speed.
a) what is R's maximum speed?

v = u + at
   = 0 + 2(4)
   = 8 m/s maximum speed

b) What distance does he run in the 4 seconds?

s = ut + 1/2 at squared 
  = 0(4) = 1/2 (2)(4)squared
  = 16 metres

c) How long will R take to finish the race?

t =  change in s/ change in v
 = 100-16m/ 8
 = 10,5sec

d) If L is 6m behind R and runs 9m/s. Who will win ?

t = 84m + 6m/ 9
  = 10 sec 'L' is faster and will win the race.

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