The depth of illumination in a water body can be measured with a
- photometer
-
secchi disc
- hydrometer
- anemometer
The correct answer is: B
Explanation
A light meter or Secchi disc is an electronic device that measures the amount of light in a given area.It can be used to measure the brightness of light at different depths in a lake or water body. Underwater light meters are also known as submersible quantum sensors or PAR (Photosynthetically Active Radiation) sensors.
Secchi disk, can also be used to measure how much light penetrates into a water body. They are 20 cm circular disks with alternating black and white segments on their surface. They are attached to a string or rope that is marked in intervals of meters or feet.