Lab 11: Radioactive Half-Life Purpose/objective: To gain insight for the meaning of the terms half-life ( t), decay constant (), and activity also called as rate of decay (dN/dt), using non-radioactive tools: virtual experiment. Equipment needed: 1. Computer 2. Paper, Pencil 3. We are observing this virtually, watch YouTube video here https://www.youtube.com/watch?v=GlUZGUQKmKQ Theory: During natural radioactive decay, not all atoms of an element are instantaneously changed to atoms of another element. The decay process takes time and there is value in being able to express the rate at which a process occurs. --------- ( 1) Where, N0 = Total no of atoms in the beginning , N = No of Remaining atoms to decay = Decay constant A useful concept is half-life, which is the time required for half of the starting material to change or decay. Half-lives can be calculated from measurements on the change in mass of a nuclide and the time it takes to occur. The only thing we know is that in the time of that substance's half-life, half of the original nuclei will disintegrate.

The throwing of coin (or we can use dice) is a random event, the same as the decay of an atom is random. As a result, coin can be used to simulate radioactive decay. Procedure: 1. Watch this you tube video. https://www.youtube.com/watch?v=GlUZGUQKmKQ 2. To simulate radioactive decay, we need to know when a die has "decayed". The easiest way is to select a color (red or yellow) to represent a "decay". For example, in the video we say red represent the decay and yellow represent the not decayed. On each through we count the no of red that are decayed and remove from the set. Take the data form the video Observation Table: Observation table: Roll Number Activity (No of Red Decayed) N (No of Yellow, Remaining) 1 117 124 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 Analysis : 1. Use graphing software (such as Microsoft Excel) to graph the number of Yellow remaining (vertical axis) as a function of the roll number (horizontal axis). 2. Your first value should be (Roll #1, 124 Yellow Dice). Fit an exponential curve/trendline to your data. Display the trendline equations on your graph.

3. Finding the half life of dice using Excel using "Trendline". Left Click on the data points to select them. Now Right Click to show a menu and select "add Trendline" Select "Exponential" Open "Options" at the top and select "Display equation on chart", then close. 2. Determine the decay constant from the best-fit equations you obtained. (HintUse Equation 1 to guide you. Your best-fit equation has this form.) 3 . Calculate the "half life" of using your best-fit trendline-determined decay constant (HintUse Equation 2 relating half life to the decay constant derived earlier in this description.) Result: Decay constant from graph =

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