Question

Once the diffraction grating has been calibrated, we will use it to measure the wavelengths of a light source. The wavelengths are then compared to the wavelengths from known elements to identify the element. Click on the link below to view the spectrum. Only the first order lines and the four most intense (brightest) are shown. (For the lab, many more lines are visible and you will need to measure more than four lines.) Read the angle for each line and then use the equation

Once the diffraction grating has been calibrated, we will use it to measure the wavelengths of a light source. The wavelengths are then compared to the wavelengths from known elements to identify the element. Click on the link below to view the spectrum. Only the first order lines and the four most intense (brightest) are shown. (For the lab, many more lines are visible and you will need to measure more than four lines.) Read the angle for each line and then use the equation Wavelength of the first line: Wavelength of the second line Wavelength of the third line Wavelength of the fourth line

Wavelength of the first line:

Wavelength of the second line

Wavelength of the third line

Wavelength of the fourth line

Answer 1

- We have to find the ware length of the lines and we have formula to find ware length by using grating diffraction. le. Td sino and t is the wavelength o is the angle between central bright and the order you are finding a d is grating element ( width of the single Slit, which is very small a generally given in question, (but here not) it is generally given in N no. of line present in I inch, and I inch = 2.54cm So N. no. of lines (or slits present in 2.54cm d = 2.54 cm, 1st line, - order (no al O, - 180° - 162' = 18 for to a d sing, = (2.54 ) x 3 in 18 cm d Sino, Binie di = 0.785 V for 2nd line order (W = 2 O2 = 180 - 160 = 20 .: d2 = dsinge - 2.54 x Sin 26 cm 422 0.4074 cm

for 3rd line, Order (n = 3 Os = 180- 158 22 Orderw = u Oy = 180 - 16 - 24 du a asinou - (2.54 x Sin 24 dy = 0.258 cm so put value of N; you will get your answer, - Remember, N (no. of lines for slits is generally giren in question,