Explanation
(a)(i) K is measured in m\(^{-1}\) and w rad s\(^{-1}\)
(ii) \(\frac{w}{k}\) represents speed of wave
w = 2\(\pi\)f; and
k = \(\frac{2 \pi}{\pi}\)
\(\frac{w}{k} \frac{2 \pi f}{2 \pi/\lambda} = f\lambda\)
But V = f\(\lambda\)
(iii) The direction of travel of the wave :s in the positive x - direction.

(b)(i) Beats are periodic rise and fall in amplitude of the sound produced when two notes of nearly equal frequencies are sounded together.
(ii) Beat frequency = \(f_1 - f_2\)
= 259 - 256 = 3Hz
(iii) f = \(\frac{1}{2L} \sqrt{T}{m}\)
259 = \(\frac{1}{2L} \sqrt{\frac{1200}{0.03}}\)
L = 0.386m

(c) 1. Both have converging or convex lenses.
2. Their interiors are black.
3. Both form real, inverted, and diminished image.
4. Images of objects are formed on the retina of the eye and the film of the camera.

