To determine the approximate altitude of the mesopause, we first need to understand what the mesopause is. The mesopause is the boundary between two layers of Earth's atmosphere: the mesosphere and the thermosphere.
Step-by-step, let's evaluate the given options:
1. Option (1) 50 km: The mesosphere typically extends from about 50 km to 85 km above Earth's surface. Therefore, 50 km would be too low to be at the boundary layer of the mesopause.
2. Option (2) 66 km: This value is within the mesosphere, but it is not at the upper boundary where the mesopause is typically found.
3. Option (3) 82 km: This value falls within the upper range of the mesosphere and is closest to the altitude where the mesopause is located.
4. Option (4) 90 km: This value is above the typical range where the mesopause is found, extending into the lower thermosphere.
Based on this evaluation, the mesopause is closest to the altitude given in option (3).
Thus, the approximate altitude of the mesopause in the atmosphere is:
(3) 82 km
