Q. Which among the following is the longest day in northern hemisphere?
Answer: June 21
Notes: The longest day in the northern hemisphere occurs on the summer solstice, which is usually June 21. On this day, the sun is directly overhead the Tropic of Cancer, which is located at 23.5° North latitude. This marks the furthest point north the sun reaches. The entire northern hemisphere experiences over 12 hours of daylight. Areas north of the Arctic Circle have 24 hours of daylight.