PHYS 1407 – Conceptual Physics II

Looking at Light

Leader: _____________________________ Recorder: ___________________________

Skeptic: _____________________________ Encourager: _________________________

Introduction

White light consists of a mixture of roughly equal amounts of all colors of light. The first person to show that white light could be split into colors was Newton. The phenomena of spitting light into its component colors is called dispersion. An instrument that splits light into its component colors and allows you to make measurements on it is called a spectrometer. In this brief activity, we will use a spectrometer to observe light emitted from a fluorescent lamp and an incandescent lamp under several conditions.

I. Observe the bright incandescent light through the spectrometer.

Q1) Describe the appearance of the light as seen through the spectrometer.

II. Observe the spectrum if the potential to the light bulb is turned down.

Q2) Describe any change in the spectrum. Think in terms of brightness, relative amounts, and so on.

III. Observe the fluorescent lights.

Q3) How is their spectrum similar to the incandescent light?

Q4) Are there any differences between the spectrum of the incandescent light and the fluorescent light?