Presentation & Questions

Multiple-Choice Questions

1. Why we are using a red LED on our receiver instead of other wavelengths led

   1. Red LEDs have longer wavelengths (around 620-750 nanometers) and lower frequencies compared to other visible light LEDs, which have shorter wavelengths and higher frequencies.

   2. Red LEDs have the highest quantum response.

   3. Red LEDs are made of aluminum gallium indium phosphide (AlGaInP) material and some of them can theoretically yield infrared wavelength.

   4. Clear LED doesn't always absorb all the wavelength unlike the colored ones

2. Why are we using an operational amplifier in the receiver circuit? 

   1. It amplifies the voltage reading from the receiver LED as the output voltage from the receiver LED is too small.

   2. It amplifies the current reading from the receiver LED as the output from the receiver LED is too small.

   3. To reduce the noise from background noises affecting the results of our photoelectric effect circuit.

   4. To bias the LED at zero volts by the virtual ground of the op-amp, and the short circuit current is converted into a voltage.

Only one answer possible per question. 

by Lynn Aung, Tin Htoo, Sean Ruiz, Lynn Thant