N21 Determining the Half-life of Thoron essays

N21 Determining the Half-life of Thoron essays N21 determining the Half-life of thoron Objective: To determine and investigate the half life of thoron The decay process of radioactive materials can be described by an exponential law. The equation is: Where f is the decay constant for the individual nuclei. N0 is the number of unstable nuclei at time t=0. Every radioactive nucleus has a definite time interval T1/2. That is the half-life. It is the number of unstable nuclei decreasing to half of original number. After the T1/2 , the number of nuclei reduces half and half. In the experiment, a thoron-air mixture is blown into an ionization chamber subject to a saturation voltage. Alpha-decay of the thorium emanation cause ion formation. This produce a current, whose ternporal progression is recorded with TY-recorder or oscilloscope. The current is the measure of the number of decays per time interval, and thus the recorded graph represents a decay curve. The experiment is to find out the half life of thoron. Radon-222 is the radioactive decay product of radium-226, which is found at low concentrations in almost all rock and soil. Thoron is the nickname for the isotope 220Rn of the element Radon. 220Rn has a 55 second half-life, much shorter than 222Rn(3.8 days). It is a noble gas generated by the decay of radium found in rocks and derived materials. It decays via alpha and beta emission through a series of short-lived progeny. It is not as common as radon in the environment. Indoors it is thought to contribute about 10% of the total airborne radiation dose. The thoron air mixture is blown into an ionization chamber. The alpha decay of thoron causes a current and records by a TY-recorder. The major error sources in the experiment is the environmental error. The environment erro ...

Spell Check Isnt Foolproof!

Spell Check Isnt Foolproof! Spell Check Isn’t Foolproof! Spell Check Isn’t Foolproof! By Mary â€Å"But it can’t have spelling mistakes! I ran spell check!† I hear this quite often. While running spell check on your documents is very important, it certainly is not a foolproof means of making sure that your documents are error free. Spell check will let you know if there is a group of letters in your document that doesn’t actually form a word. If you type â€Å"fjdklfjdlf† into a document, spell check will catch that this isn’t an actual word. However, if you send an email to your mom asking her to buy you a new â€Å"pear of pants,† spell check won’t let you know that you should have used pair instead of pear. No matter how careful you are with spell check, there is no substitute for (a) proofreading your work yourself and (b) having someone else proof it for you. There’s no substitute for a common sense check. There are too many similar words in a language to ever be able rely 100% on spell check to get rid of all of your spelling errors. I’m a professional writer and business communications trainer, and I know from personal experience that you can’t always trust spell check. One of my more entertaining typos that spell check didn’t catch occurred in an article I wrote a few weeks ago about wedding anniversary gifts. This is what I wrote: with love and infection This is what I meant: with love and affection Fortunately, I proofed my work before sending it to the client for publication. I laughed when I caught the error, because it is kind of funny and ironic, but I don’t think my client would have been very entertained. If the article had gone to the client with this mistake, I could very well have lost a project. Don’t use spell check as a crutch. Don’t take a chance on losing business or sounding ignorant just because you won’t take the time to proofread your work. Just remember there’s no substitute for common cents. Oops, sense! Darn that spell check! Want to improve your English in five minutes a day? Get a subscription and start receiving our writing tips and exercises daily! Keep learning! Browse the Spelling category, check our popular posts, or choose a related post below:7 English Grammar Rules You Should KnowThat vs. WhichGlimpse and Glance: Same or Different?