Physics Paper 1, MAy/June. 2011
 Questions: 1 2 3 4 5 6 Main
Weakness/Remedies
Strength

Alternative b
Question 4

(a)  Diagram

You are provided with two retort stands, two metre rules, pieces of thread and other
necessary apparatus.

1. Set-up the apparatus as illustrated above ensuring that  the strings are permanently 10 cm from either end of the rule.
2. Measure and record the length L = 80 cm of the two strings.
3. Hold both ends of the rule and displace the rule slightly, then release so that it oscillates about a vertical axis through its centre.
4. Determine and record the time t for 10 complete oscillations.
5. Determine the period T of oscillations
6. Evaluate log T and log L,
7. Repeat the procedure for four other values of L = 70, 60, 50 and 40 cm.
9. Plot a graph with log T on the vertical axis and log L on the horizontal axis.
10. Determine the slope, s, and the intercept, c on the vertical axis.
11. State two precautions taken to ensure accurateresults.

b (i)   Define simple harmonic motion
(ii)    Determine the value of L corresponding to  t = 12s from the graph in (a) above.
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Observation

The observation and its tabulation were well handled by most responding candidates.  However, the evaluation of Log L and Log T to the nearest decimal places was poorly tackled.

The plotting of the graph of log T against Log L was poorly handled.  Evaluation of slope and determination of intercept on the vertical axis was fairly attempted.  Candidates were able to state the precautions correctly in acceptable language.

The part b was fairly handled by most responding candidates as they were able to define simple harmonic motion but could not satisfactorily deduce the value of L from the graph when t = 12s probably because of  the Logarithm involved.

In part (a) candidates are expected to:

-    Measure and record five values of L to at least 1 d.p. and in trend.
Trend: As L increases, t, decreases
-    Evaluate five values each of T, log L and log I to at least 3 s.f.
-    Record data in composite table
-    Plot five point, correctly using reasonable scales and distinguished axes
-    Draw line of best fit.
-    Determine the intercept on the vertical axes and the slope of the graph using large
right-angled triangle.

State any two of the following precautions in acceptable language.

-     Ensured supports of pendula were rigged
-     Avoided parallax error on meter rule/stop watch
-     Zero error was noted and corrected on metre rule/stop watch/clock
-     Ensured smooth and regular oscillations in a horizontal plane
-     repeated readings shown on table