An electromagnetic wave falls normally on a diffraction grating. A second-order maximum appears at an angle of $30^\circ$ to the direction of the incident light. The diffraction grating contains 5000 lines per cm. Determine the wavelength of the wave.
- A$2.5 \times 10^{-7}\,\text{m}$
- B$5.0 \times 10^{-7}\,\text{m}$
- C$1.0 \times 10^{-6}\,\text{m}$
- D$5.0 \times 10^{-5}\,\text{m}$