You are provided with an illuminated object, converging lens, screen, metre rule, and other necessary materials.
Measure and record the size \(a_o\) of the illuminated object.
Place the object O and the screen S on Opposite sides of the converging lens L.
Set the distance between the object and the lens U = 30cm.
Adjust the screen until a sharp image of the illuminated object is obtained on the screen.
Measure and record the size a of the image.
Evaluate m = \(\frac{a}{a_{0}}\), and m\(^{-1}\)
Repeat the procedure for four other values of U=35cm, 40cm, 45cm and 50cm respectively.
Tabulate your readings.
Plot a graph with m\(^{-1}\) on the vertical axis and U on the horizontal axis.
Determine the slope, s, of the graph and intercept, C, on the vertical axis.
Determine the value of U for which m\(^{-1}\)=0.
State two precautions taken to obtain accurate results.
(b)i. Using your graph, determine the value of m for which U= 37cm.
ii. Sketch a diagram to illustrate how a converging lens may be used to produce a real diminished image of an object.
Verified Correct Answer: .
Physical Principles & Numerical Solution
a = 1.5cm
u/cm
\(\frac{a}{cm}\)
M=\(\frac{a}{d}\)
m\(^{-1}\)
30.0
2.2
1.467
0.682
35.0
1.5
1.000
1.000
40.0
1.2
0.800
1.250
45.0
0.9
0.600
1.667
50.0
0.7
0.467
2.141
Slope (s) = \(\frac{\bigtriangleup {m}^{-1}}{\bigtriangleup {y}}\) = \(\frac{2.4 - 0.4}{54 - 24} = \frac{2}{30}\) = 0.06
\(X_1\) = when m\(^{-1}\) = 0
u = 23cm
Precautions; i
- avoided error due to parallel when taking readings on the metre rule.
- made sure that, I took the height of the image when it is sharp.
- ensured that the intensity of the source of light was maintained.
- took repeated readings to avoid random errors.
(b)i. When U iss 37cm
37 = 1.01m\(^{-1}\)
37 x \(\frac{1.01}{m}\)
m = \(\frac{1.01}{37}\)
m = 0.03
ii. Object beyond 2F\(^{1}\)
Source: Myschool Past Questions Archive (Record #59977)