Light with wavelength $5.4 \times 10^{-7}\,\text{m}$ is directed normally onto a diffraction grating. The spacing between neighbouring lines in the grating is $2.0 \times 10^{-6}\,\text{m}$. The light leaving the grating is received by a semicircular screen, as shown in the view from above. The grating is positioned at the centre of the semicircle, and the grating lines are vertical. How many bright spots are produced on the screen?
- A3
- B4
- C6
- D7