= 1.3 (m) (1) (1.28) 2 (iii) (c = f = 108 × (a)(ii) (1) λ) = 138 to 140(.4) (m s–1) (1) ecf from (a) (ii) 2 (b) (i) four antinodes (1) (single or double line) first node on 0.16 m (within width of arrowhead) + middle node between the decimal point and the centre of the in m’ ‘m’ ‘0.64 + middle 3 nodes labelled or (1) ‘N’, ‘n’ ‘node’ 2 (ii) (4 =) 430 (Hz) (432) f0 (1) or use of f = 430 to 440 Hz correct answer only, no ecf 1 (c) decrease the length/increase tension/tighten string (1) 1 [9] M23. (a) showed that light was a wave (rather than a particle)/wave nature (of light) (1) 1 (b) (i) single wavelength (or frequency) (1) 1 (ii) (waves/source(s) have) constant phase difference (1) 1 (iii) any sensible precaution, eg do not look into laser/do not point the laser at others/do not let (regular) reflections enter the eye/safety signs/suitable safety goggles (1) 1 (c) (0.16/8) = 0.02(0) (1) = (1) ecf from calculation of fringe spacing
= 1.3 (m) (1) (1.28) 2 (iii) (c = f λ) = 108 × (a)(ii) (1) = 138 to 140(.4) (m s–1) (1) ecf from (a) (ii) 2 (b) (i) four antinodes (1) (single or double line) first node on 0.16 m (within width of arrowhead) + middle node between the decimal point and the centre of the ‘m’ in ‘0.64 m’ + middle 3 nodes labelled ‘N’, ‘n’ or ‘node’ (1) 2 (ii) (4 f0 =) 430 (Hz) (1) (432) or use of f = 430 to 440 Hz correct answer only, no ecf 1 (c) decrease the length/increase tension/tighten string (1) 1 [9] M23. (a) showed that light was a wave (rather than a particle)/wave nature (of light) (1) 1 (b) (i) single wavelength (or frequency) (1) 1 (ii) (waves/source(s) have) constant phase difference (1) 1 (iii) any sensible precaution, eg do not look into laser/do not point the laser at others/do not let (regular) reflections enter the eye/safety signs/suitable safety goggles (1) 1 (c) (0.16/8) = 0.02(0) (1) = (1) ecf from calculation of fringe spacing
AS-Waves-and-Optics.docx