The wavelength \( \lambda \) and frequency \( \nu \) of a photon are related by the equation:
\[
c = \lambda \nu
\]
Where:
- \( c \) is the speed of light,
- \( \lambda \) is the wavelength,
- \( \nu \) is the frequency.
When the wavelength \( \lambda \) is doubled, the frequency \( \nu \) becomes halved, because the speed of light \( c \) is constant. Therefore:
\[
\nu' = \frac{\nu}{2}
\]
The wave number \( k \), which is the reciprocal of the wavelength, is given by:
\[
k = \frac{1}{\lambda}
\]
When the wavelength is doubled, the wave number becomes halved:
\[
k' = \frac{k}{2}
\]
Thus, the wave number becomes \( \frac{1}{2} \) times, and the frequency becomes \( \frac{1}{2} \) times.
Thus, the correct answer is:
% Correct Answer
Correct Answer:} \( \frac{1}{2} \), \( \frac{1}{2} \)