The blue end of the visible color spectrum has wavelengths, and the red end has wavelengths.

Blue end has shorter wavelength and red end has longer wavelengths.

Explanation:

Visible region consists of Violet, Indigo, Blue, Green, Yellow, Orange and Red. These colors are arranged in the order of increasing wavelengths which means that blue region has shorter wavelength and as we move towards red region, the wavelength of light increases.

Blue region has shorter wavelength and higher frequency whereas red region has longer wavelength and smaller frequency.

Frequency and wavelength follow inverse relation.

Speed of Agnes during her journey was 0.848c

Explanation:

Given that;

Age of Agnes t₀ = 20 years

distance d = 2 × distance of star from Earth = 2 × 16 light-years

= 32 light-years

so get her speed speed; we use the following expression

Yvt₀ = d

( v / √(1 - ()²) )² = ( 32 light-years / 20 yrs )²

v² / (1 - ( v²/c²)) = ( 32 × c  / 20 )²

v² / (1 - ( v²/c²)) = 2.56 × c²  

v² / c²-v²/c² = 2.56 × c²  

v²c²  / c² - v²  = 2.56 × c²  

v²  / c² - v²  = 2.56

v²  = 2.56 (c² - v²)

v²  = 2.56 (c² - v²)

v²  = 2.56c² - 2.56v²

v² + 2.56v² = 2.56c²

3.56v² = 2.56c²

v² = (2.56/3.56)c²

v = √((2.56/3.56)c²)

so v = 0.848c

Therefore, Speed of Agnes during her journey was 0.848c