Final answer:
The subsolar point is at the Tropic of Capricorn, not the Tropic of Cancer, on December 21, which is the winter solstice in the Northern Hemisphere. The Tropic of Cancer is the location of the subsolar point on or about June 21, during the Northern Hemisphere's summer solstice.
Step-by-step explanation:
The subsolar point is not at the Tropic of Cancer on or about December 21. Instead, on this date, which is the winter solstice in the Northern Hemisphere, the subsolar point is at the Tropic of Capricorn.
The Tropic of Cancer is the parallel at 23.5 degrees north of the equator and receives direct sunlight during the Northern Hemisphere's summer, specifically on or about June 21. Conversely, the Tropic of Capricorn, at 23.5 degrees south of the equator, receives direct sunlight during the Southern Hemisphere's summer, including December 21 or 22. This is due to Earth's tilt of 23.5 degrees which results in seasonal variations.
On the winter solstice, the North Pole experiences 24 hours of darkness, while the South Pole enjoys 24 hours of daylight. Consequently, for observers located on the Tropic of Cancer, the Sun would be at an altitude of 44° at noon on December 21, as the Sun is approximately 23° south of the celestial equator on that date.
Thus, from the Tropic of Cancer (23.5° N), the altitude of the Sun will be 90° - 46° = 44° above the horizon.