a) You are observing a gas lamp of an unknown element illuminating a diffraction grating of 50 lines/mm and take note of two of the spectral lines on a screen 1.50 m away. These two lines show up on the screen as shown to the right. Below is the spectrum of a few elements, which element do you believe is in the lamp? 500nm 600nm 400nm H He Li k Na Ca Sr Ba 700nm 800nm -4.50 mm 3.68cm -0.00 mm .-3.68 cm -4.50 mm

a) You are observing a gas lamp of an unknown element illuminating a diffraction grating of 50 lines/mm and take note of two of the spectral lines on a screen 1.50 m away. These two lines show up on the screen as shown to the right. Below is the spectrum of a few elements, which element do you believe is in the lamp? 500nm 600nm 400nm H He Li k Na Ca Sr Ba 700nm 800nm -4.50 mm 3.68cm -0.00 mm .-3.68 cm -4.50 mm