On Fig. 5.1, mark the position of an interference maximum with a cross (x), and label it Y.
On Fig. 5.1, mark the position of an interference minimum with a cross (x), and label it Z.
The waves in air have wavelength $2.9 \times 10^{-5}\,\text{m}$. An interference pattern is observed along a line parallel to AB and a perpendicular distance of $140\,\text{m}$ from AB. The separation between neighbouring interference maxima is $1.2\,\text{cm}$. Calculate the separation $a$ of the sources A and B.
State the main region of the electromagnetic spectrum to which the waves belong.
On Fig. 5.1, show the answer with a cross (\times):
The waves in air have wavelength $2.9 \times 10^{-5}\,\text{m}$. An interference pattern is observed along a line parallel to AB and at a perpendicular distance of $140\,\text{m}$ from AB. The separation between neighbouring interference maxima is $1.2\,\text{cm}$.