Final answer:
The peak wavelength emitted by a star with a surface temperature of 19,801 K is 146.5 nm.
Step-by-step explanation:
The peak wavelength (λmax) emitted by a star can be calculated using Wien's law, which states that as the temperature of an object increases, the peak wavelength of its emitted radiation decreases. The formula for Wien's law is λmax = 2.9 × 10^6 / T, where λmax is the peak wavelength in nanometers and T is the temperature in kelvin. Given that the surface temperature of the star is 19,801 K, we can substitute this value into the formula to find the peak wavelength:
λmax = 2.9 × 10^6 / 19801 = 146.5 nm
Therefore, the peak wavelength emitted by the star is 146.5 nm.