Question

At what inclination to the ground are soil thermometers installed in the observatory?

• A. 30 degrees
• B. 45 degrees
• C. 60 degrees
• D. 90 degrees

Hint:

Soil thermometers: Planted vertically (90°) to measure temperature at specific soil depths.

Answer 1

The Correct Option is D

Soil thermometers in meteorological observatories are installed {vertically (90 degrees to the ground) to measure soil temperature at standardized depths (e.g., 5 cm, 10 cm, 20 cm, 50 cm). Vertical installation ensures precise and consistent readings across different soil layers, which are critical for agricultural, meteorological, and environmental studies. Angles like 30, 45, or 60 degrees would lead to inaccurate or non-standardized measurements, as they would not align with the depth-specific protocols. Thus, option (4) is correct.

Answer 2

Purpose-based reasoning:
A soil thermometer must record the temperature of soil layers lying directly beneath a fixed surface point, at specific depths such as 5, 10, 20 and 30 cm. This is only achievable if the sensing bulb travels straight down along a vertical line below its surface marker; any slanted installation at 30, 45 or 60 degrees would place the bulb off to one side, mixing readings from a range of depths rather than one exact depth. Only a 90 degree, vertical, installation guarantees the bulb sits exactly at the stated depth directly under the surface point, so option (4) is correct.