Physics Laboratory Lab14.IA
Physics Laboratory Lab14.IA
Physics Laboratory Lab14.IA
Lab #: 14
References:
• Maths Unlimited CSEC Physics Lab Manual
• Physics for CSEC (3rd edition) Chapter 3 (Acquiring Experimental Skills) STRONGLY
RECOMMENDED
• A satisfactory result for the value of a quantity is one that is near to the ‘true’value or the
‘accepted’ or ‘expected’ value of that quantity.
• It is important that the appropriate instrument be used when measuring. Ordinarily, a rough
comparison with a numerical scale, taken at a glance and given in round numbers, is
adequate.
• The precision of an instrument is the maximum error there can be inmeasuring the size of a
quantity with that instrument. Precision is also relatedto the width of the range of values
within which the true value lies.
• If you are aware or given any theoretical values for a particular lab result, it is advisable to
discuss how close the experimental result is to the theoretical result.
• More often, the precisionof the instrument used indicate the degree of significance shown by
the result.For example, the external diameter of glass tubing may be stated as 0.56 cm if it
was measured with a Vernier Caliper. This tells the reader that the calliper measured to the
nearest 0.01 cm this also represents the Uncertainty/S.D of the instrument.
• Range is the difference between the highest value and the lowest value on the scale of an
instrument (simplest definition)
• An isotope is each of two or more forms of the same element that contain equal numbers of
protons but different numbers of neutrons in their nuclei, and hence differ in relative atomic
mass. It is the radioactive form of an element.
• Natural radioactivity or nuclear decay is a radioactive decay process in which at a given time a
certain number of atoms disintegrate spontaneously.
• It is said to be random because:
2. Each nucleus in sample have the same chance of decaying per unit time
• In this process unstable atoms emit ionizing particles or radiations and eventually reach a stable
state. Atoms always want to be stable
• There are three MAIN types of nuclear decay, namely 1. Alpha decay 2. Beta decay 3. Gama
decay.
• A basic concept of radioactive decay is that the probability of decay for each type of radioactive
nuclide is constant. In other words, there are a predictable number of decays per second even
though it is not possible to predict which nuclei among the sample will decay. A quantity called
the “decay constant,” or λ, characterizes this concept. In other words λ is probability of a
nucleus decaying in the next second.
• In a radioactive decay process, the rate at which atoms undergo decay is proportional to the
number of atoms initially present at a given instant of time
• The half-life of an element undergoing radioactive decay is the time for the amount of
radioactive material to become half of its initial value.
• The nuclear decay process can be simulated by rolling of dice repeatedly, taking out a particular
species of dice each time from the lot.
• In this simulation, N1 represents the initial number of dice taken (100 number of similar dice),
N(t) is the number dice remaining after each round of rolling (undecayed nuclei) and it
corresponds to the number of rounds rolled or thrown (equivalent to time taken).
Lab # 14
Diagram:
None
Procedure:
Results:
• From the graph answer question 2 AND 3 under ‘data analysis’ in lab manual
DISCUSSION /INTERPRETATION
• Define Radioactive decay and half life
• Answer questions and follow instructions in lab manual, e.g If your classmates do the experiment,
would they get the same results?
• The curve represents an exponential decay of…………………………
• Include main results
Sources of error/Limitations:
• Dice not shaken properly will yield near predictable results
Precaution:
Conclusion: