(a(i))[1]
State the name for the region around A shown in the diagram.
(a(ii))[1]
State the name for the region around B shown in the diagram.
(b)[1]
On Fig. 6.1, draw a double-headed arrow to indicate one wavelength.
(c)[3]
State and explain any change that would occur in the wavefront pattern shown in Fig. 6.1.
(d)[3]
State and explain any change in the pattern of wavefronts shown in Fig. 6.1.