# Differences

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 phy252:hydrogenemissionspectrum [2018/11/07 14:28]mdawber [Measurement] phy252:hydrogenemissionspectrum [2018/11/07 14:28] (current)mdawber [Measurement] Both sides previous revision Previous revision 2018/11/07 14:28 mdawber [Measurement] 2018/11/07 14:28 mdawber [Measurement] 2018/11/07 14:26 mdawber [Measurement] 2017/03/11 18:33 mdawber [Analysis] 2017/03/11 18:31 mdawber [Introduction] 2017/03/11 18:31 mdawber 2017/03/11 18:28 mdawber [Analysis] 2017/03/11 18:28 mdawber 2017/03/11 18:27 mdawber [Measurement] 2017/03/11 18:26 mdawber [Measurement] 2017/03/11 18:26 mdawber 2017/03/11 18:21 mdawber [Introduction] 2017/03/11 18:20 mdawber [Introduction] 2017/03/11 18:19 mdawber 2017/03/11 18:16 mdawber 2017/03/11 18:16 mdawber 2017/03/11 18:15 mdawber created 2018/11/07 14:28 mdawber [Measurement] 2018/11/07 14:28 mdawber [Measurement] 2018/11/07 14:26 mdawber [Measurement] 2017/03/11 18:33 mdawber [Analysis] 2017/03/11 18:31 mdawber [Introduction] 2017/03/11 18:31 mdawber 2017/03/11 18:28 mdawber [Analysis] 2017/03/11 18:28 mdawber 2017/03/11 18:27 mdawber [Measurement] 2017/03/11 18:26 mdawber [Measurement] 2017/03/11 18:26 mdawber 2017/03/11 18:21 mdawber [Introduction] 2017/03/11 18:20 mdawber [Introduction] 2017/03/11 18:19 mdawber 2017/03/11 18:16 mdawber 2017/03/11 18:16 mdawber 2017/03/11 18:15 mdawber created Line 43: Line 43: ===== Measurement ===== ===== Measurement ===== - The spectrometer is now ready to measure wavelengths;​ make sure you understand how to read the vernier scale for the angles ([[http://​whistleralley.com/​surveying/​vernier/​}|Some instructions ]] or a [[https://​www.youtube.com/​watch?​v=GtxMd-w90Hk|YouTube Video explaining how]]). Place the hydrogen source so that the light falls into the collimator. Insert the grating in its slot after reading off the spacing $d$. Now slowly change the angle setting of the telescope until you see a line. Read the angle. Continue until you see the next line (it will have a different color) and so on. You should see three + The spectrometer is now ready to measure wavelengths;​ make sure you understand how to read the vernier scale for the angles ([[http://​whistleralley.com/​surveying/​vernier/​|Some instructions ]] or a [[https://​www.youtube.com/​watch?​v=GtxMd-w90Hk|YouTube Video explaining how]]). Place the hydrogen source so that the light falls into the collimator. Insert the grating in its slot after reading off the spacing $d$. Now slowly change the angle setting of the telescope until you see a line. Read the angle. Continue until you see the next line (it will have a different color) and so on. You should see three different colors. The first one is actually most difficult to see. If you rotate still further you will see the same sequence of lines appearing again, but much fainter. This is the second order pattern ($n=2$). Try to see as many lines and orders as possible. Repeat this sequence of measurements on the opposite side of the spectrometer. This gives better different colors. The first one is actually most difficult to see. If you rotate still further you will see the same sequence of lines appearing again, but much fainter. This is the second order pattern ($n=2$). Try to see as many lines and orders as possible. Repeat this sequence of measurements on the opposite side of the spectrometer. This gives better precision in the measured angles: for each line and order you have now a pair of measured angles $\theta_{L}<​0$ and $\theta_{R}>​0$,​ and $\theta=\frac{\theta_{R}-\theta_{L}}{2}$. precision in the measured angles: for each line and order you have now a pair of measured angles $\theta_{L}<​0$ and $\theta_{R}>​0$,​ and $\theta=\frac{\theta_{R}-\theta_{L}}{2}$.