Final answer:
The angle of the second-order maximum can be found using the equation for diffraction with slit separation and wavelength, but without additional details relating to wavelength or slit separation, we cannot give a precise answer.
Step-by-step explanation:
The student's question is related to diffraction and interference patterns observed when light passes through a double slit or a diffraction grating. In physics, the angle for different orders of maximum intensity in an interference pattern can be calculated using the equation d sin(\theta) = m \lambda, where d is the slit separation, \theta is the angle of the maximum, m is the order number, and \lambda is the wavelength of the light. To find the angle for the second-order maximum, one could use this equation with m set to 2 and the values provided from earlier observations or calculations.
For the second-order maximum specifically, if the first-order maximum arises at 20.0°, we would expect the second-order maximum to occur at a larger angle, because as m increases, so does the angle \theta for a given wavelength and slit separation. Nevertheless, the exact value would require additional information such as the wavelength of light or the slit separation. If any of those were provided, we could use the equation to calculate the angle more precisely.