Lines drawn on a map connecting places with equal duration of sunshine are called

Step 1: Analyze the question The question asks for the name of lines on a map joining places that have the same duration of sunshine.

Step 2: Explain the concept Isolines (lines of equal value) take their names from a Greek prefix "iso-" (meaning equal) plus a word for what is being measured:

• Isohel: from "helios" (sun), so lines joining places with equal duration or amount of sunshine
• Isotherm: from "therme" (heat), so lines joining places with equal temperature
• Isoneph: from "nephos" (cloud), so lines joining places with equal cloud cover
• Isohyet: from "hyetos" (rain), so lines joining places with equal rainfall

Step 3: Match to the question The question is about sunshine duration, and "helios" means sun. So the correct term is isohel.

• B (isotherms) is about temperature, so it is wrong.
• C (isonephs) is about cloud cover, so it is wrong.
• D (isohyets) is about rainfall, so it is wrong.

Answer: A. isohels

Exam tip: Link the Greek root to the weather element:

• Hel = Helios = Sun
• Therm = Thermal = Heat
• Neph = Cloud (think "nephology," the study of clouds)
• Hyet = Rain (think "hydro" and "wet")

Others you may see: isobars (pressure), isohaline (salinity), isobaths (ocean depth), contours (height of land).