Abbreviations:
WK1: Intro to Optical Equipment b/w = between
Wednesday, October 7, 2020 10:02 AM w/ = with
V = voltage
I = current
D = displacement
INTRODUCTION: R = resistance
• Goal is to become familiar with measuring light intensity using a photometer.
EXPERIMENTAL SETUP:
• Clamp photometer onto the optical bench (50cm away from laser) and align is so that the laser (10cm away from end of optical bench ruler) beam continues to strike the meter even as it moves along the optical
bench.
• Photometer puts out a voltage signal that is proportional to the intensity of the incident of light-- voltage is displayed by the digital multimeter (DMM).
○ Converts light into an electric current.
• Photoelectric effect: as light hits metal, electrons are emitted from the metal and produce a current (I) which is amplified by the photometer and converted into voltage (V) by the DMM.
○ Photons: tiny quantized packets of light.
• *Saturation occurs when the metal reaches the maximum flux of electrons it can produce, or when the metal reaches the maximum amplification on the photometer.*
• Important characteristics of the photometer:
○ Transverse sensitivity: the photometer is extremely sensitive to the position where the laser beam hits the photometer face. Keep the longitudinal distance (length) b/w the laser and the photometer
constant; rotate the laser slightly, as to move the laser beam across the glass face of the photometer. -> Voltage output will vary significantly.
1. Find the position of the laser beam in the photometer window for which you obtain the highest voltage output.
2. Obtain the background signal by blocking the photometer window w/ your hand.
3. Plot "D versus V" to observe sensitivity.
i. Here, "D" is equal to the displacement of laser beam across the photometer’s window, measured in mm. This is across the photometer, moving left or right.
○ Saturation: Set desk lamp at low intensity and w/ an initial separation of 2 feet. As you move the photometer towards the desk lamp the voltage does not increase after it reaches ~1V. -> This indicates the
photometer is saturated.
4. Place desk lamp at the 100 centimeters mark on the optical bench ruler.
WK1: Intro to Optical Equipment b/w = between
Wednesday, October 7, 2020 10:02 AM w/ = with
V = voltage
I = current
D = displacement
INTRODUCTION: R = resistance
• Goal is to become familiar with measuring light intensity using a photometer.
EXPERIMENTAL SETUP:
• Clamp photometer onto the optical bench (50cm away from laser) and align is so that the laser (10cm away from end of optical bench ruler) beam continues to strike the meter even as it moves along the optical
bench.
• Photometer puts out a voltage signal that is proportional to the intensity of the incident of light-- voltage is displayed by the digital multimeter (DMM).
○ Converts light into an electric current.
• Photoelectric effect: as light hits metal, electrons are emitted from the metal and produce a current (I) which is amplified by the photometer and converted into voltage (V) by the DMM.
○ Photons: tiny quantized packets of light.
• *Saturation occurs when the metal reaches the maximum flux of electrons it can produce, or when the metal reaches the maximum amplification on the photometer.*
• Important characteristics of the photometer:
○ Transverse sensitivity: the photometer is extremely sensitive to the position where the laser beam hits the photometer face. Keep the longitudinal distance (length) b/w the laser and the photometer
constant; rotate the laser slightly, as to move the laser beam across the glass face of the photometer. -> Voltage output will vary significantly.
1. Find the position of the laser beam in the photometer window for which you obtain the highest voltage output.
2. Obtain the background signal by blocking the photometer window w/ your hand.
3. Plot "D versus V" to observe sensitivity.
i. Here, "D" is equal to the displacement of laser beam across the photometer’s window, measured in mm. This is across the photometer, moving left or right.
○ Saturation: Set desk lamp at low intensity and w/ an initial separation of 2 feet. As you move the photometer towards the desk lamp the voltage does not increase after it reaches ~1V. -> This indicates the
photometer is saturated.
4. Place desk lamp at the 100 centimeters mark on the optical bench ruler.
