Matriculation Physics Experiment 2 (Malaysia)

PHYSICS LAB REPORT SEMESTER 1 EXPERIMENT 1

ITEMS TOPIC OBJECTIVE THEORY

CONTENTS MEASUREMENT AND UNCERTAINTY To measure and determine the uncertainty of length of various objects Measuring some physical quantities is part and parcel of any physics experiment. It is important to realise that not all measured values are exactly the same as the actual values. This could be due to errors that we made during the measurement or perhaps the apparatus t hat we use may not be accurate or sensitive enough. Therefore as a rule the uncertainty of a measurement must be taken and it has to be recorded together with the measured value. The uncertainty of the measurement depends on the type pf measurement and how it is done. For a quantity x with the uncertainty ∆x , its measurement is recorded as below : x ±

∆x

The relative uncertainty of the measurement is defined as : ∆x ∕ x And therefore its percentage of uncertainty is ∆ x ∕ x × 100%.

1.1

Single Reading a)

If the reading is taken from a single point or at the end of the scale, ∆x = ½ x (smallest division from the scale)

b)

If the reading are taken from two points on the scale, ∆x = 2 x [ ½ x (smallest division from the scale)]

c)

If the apparatus used the vernier scale, ∆x = 1 x (smallest unit from the vernier scale)

1.2

Repeated Readings For a set of

n

repeated measurements of  x , the best value

is the average value given by

̅ 

∑ =1  

MARKS

where n = the number of measurements taken x = the ⅈℎ  measurement The uncertainty is given by

∆ 

∑ =1

|̅ −   | 

The result should be written as x

APPARATUS

NO 1 2 3 4 5 6 7 8

NAME Metre rule Vernier callipers Micrometer screw gauge Travelling microscope Coin (new edition) Glass rod Ball bearing Capillary tube (1 cm long)

= ̅ ± 

RANGE (0.0 – 100.00) cm (0.00-15.00) cm (0.00-25.00) mm

SENSITIVITY 0.1cm 0.01cm 0.01mm

(0.00-220.00)mm

0.01mm

-

-

-

-

PROCEDURE 1. Choose the appropriate instrument for measurement of (i) Length of a laboratary manual. (ii) Diameter of a coin. (iii) External diameter of a glass rod. (iv) Diameter of a ball bearing. 2. For task (i) to (iv), perform the measurement and record your results in a suitable table for at least 5 readings. Refer to Table 1.1 as an example. Determine the percentage of uncertainty for each set of readings. 3. Use travelling microscope to measure the internal diameter of the capillary tube. Adjust the microscope so that the cross-hairs coincide with the left and right edge of the internal diameter of the tube. The internal diameter, d= | ℎ −  |

DATA

No.

Length of the laboratory manual,

|  ̅ −  |

 1 2 3 Average No. 1 2 3 Average

Diameter of coin

|  ̅ −  |

No. 1 2 3 Average

External diameter of glass rod

|  ̅ −  |

No. 1 2 3 Average

Diameter of a ball bearing

|  ̅ −  |

No. 1 2 3 Average

Diameter of capillary tube

|  ̅ −  |

OBSERVATION Calculation for the average reading for each item: 1) Length of laboratory manual (A+B+C)cm ÷ 3 = cm 2) Diameter of coin (A+B+C)cm ÷ 3 = cm 3) External diameter of glass rod (A+B+C)cm ÷ 3 = mm

4) Diameter of ball bearing (A+B+C)mm ÷ 3 = mm 5) Diameter of capillary tube (A+B+C)cm ÷ 3 = cm DISCUSSION CONCLUSION REFERENCES