An astronomer observes the full moon through a telescope. The mischievous man covers with his hand the half of the lens

An astronomer observes the full moon through a telescope. The mischievous man covers with his hand the half of the lens, right from the astronomer. How has the telescope’s view of the moon changed?

The moon has not changed, but the image brightness has decreased.

Remember: The process of learning a person lasts a lifetime. The value of the same knowledge for different people may be different, it is determined by their individual characteristics and needs. Therefore, knowledge is always needed at any age and position.