Assessment Schedule 2015 Physics: Demonstrate understanding of aspects of wave behaviour (90938)

Transcription

1 NCEA Level 1 Physics (90938) 2015 page 1 of 7 Assessment Schedule 2015 Physics: Demonstrate understanding of aspects of wave behaviour (90938) Assessment Criteria with Merit with Excellence Demonstrate understanding of aspects of wave behaviour involves: Demonstrating awareness of sound wave propagation and properties of sound waves. Demonstrate in-depth understanding of aspects of wave behaviour involves: Showing how sound wave propagation relates to particle motion and to properties of sound wave. Demonstrate comprehensive understanding of aspects of wave behaviour involves: Providing evidence that shows how concepts of wave properties and wave propagation relate to situation of echolocation. Evidence Q with Merit with Excellence ONE (a)(i) (ii) Longitudinal wave. 2 wavelengths. Defines a wavelength / explains using diagram. Longitudinal wave. 2 wavelengths, because wavelength is distance between one compression to next compression / repeating pattern. (b) (c) Particles move parallel/in same direction as wave movement. Calculates a period using frequency of 150 Hz to get answer of Use of T 1/ but left as fraction. Incorrect rounding of T = but missing / incorrect unit. Particles move back and forth / vibrate / oscillate in same direction/parallel to wave motion. T = 1 f = = s

2 NCEA Level 1 Physics (90938) 2015 page 2 of 7 (d)(i) (Correctly calculates: (Correctly calculates : (Correctly calculates : v seawater = = (m s 1 )) v seawater = = (m s 1 )) v seawater = = (m s 1 )) Calculates a distance without halving (time or distance): E.g. d = Correct calculation (halving time or distance), correct answer but missing/incorrect unit Correct calculation (halving time or distance), correct answer, correct unit 2d = = d = v t = = 20.6 Correct calculation (halving time or distance) but incorrect answer 2d = = m d = = 46.3 (46) = m d = = 46.3 (46) m (ii) An echo from a near object arrives earlier/in a shorter time/quicker/faster than that from a distant object. (Since velocity of sound in water remains constant) an echo from a near object arrives earlier / in a shorter time (not quicker ) than that from a distant object. E7: (Since velocity of sound in water remains constant) an echo from a near object arrives earlier/in a shorter time (not quicker ) than that from a distant object. The dolphin uses time delay to distinguish between near object and distant object. E8: The dolphin uses time delay to distinguish between near object and distant object. NØ N1 N2 A3 A4 M5 M6 E7 E8 No response; no relevant Very little Some evidence at level; partial explanations. is at Nearly all Some Merit level with remainder at is at Merit level with some at most tasks with evidence at Excellence level weak or incomplete. most tasks with evidence at Excellence level accurate and full. As above. 1a 2a 3a 1e + 1a 1m + 1a 4a 2m 1e + 2a 1e + 1m 3m 1(d) is correct 1(d) is correct including how dolphin uses time delay

3 NCEA Level 1 Physics (90938) 2015 page 3 of 7 Q with Merit with Excellence TWO (a) Diagram showing diffraction of waves with at least 3 wave fronts shown but wavelength not kept same/curve not precise. Correct diagram showing diffraction of waves with at least 3 wave fronts shown with no change in wavelength. (b) (c)(i) Diffraction. Calculated wavelength correctly. (i) Correct wavelength calculation. λ = 65 5 = 13 m (ii) Calculated speed using wrong wavelength from (i). Correct calculation of speed but missing/incorrect unit v = f λ = = 3.25 (3.3) m s 1

4 NCEA Level 1 Physics (90938) 2015 page 4 of 7 (d)(i) Any ONE of following: Angle of incidence = = 35 Angle of reflection is equal to angle of incidence. Any TWO of following: Angle of incidence = = 35 Angle of reflection is equal to angle of incidence. E7: Angle of incidence is = = 35 Angle of reflection is equal to angle of incidence. : Ray bends towards normal when going from seawater to plastic Ray bends towards normal when going from seawater to plastic Ray bends towards normal when going from seawater to plastic Ray bends away from normal when going from plastic to air Ray bends away from normal when going from plastic to air Ray bends away from normal when going from plastic to air (Correct arrows drawn on rays) (Correct arrows drawn on rays) States that reflected ray has same speed as incoming ray. States that reflected ray has same speed as incoming ray because both waves travelling in same medium. (Reflection does not cause a change in speed.) States that reflected ray has same speed as incoming ray because both waves travelling in same medium. (Reflection does not cause a change in speed.) E8: Plus states / implies Angle of incidence is measured from normal. (Ray bends more away from normal compared to amount it bends towards normal from seawater to plastic.)

5 NCEA Level 1 Physics (90938) 2015 page 5 of 7 NØ N1 N2 A3 A4 M5 M6 E7 E8 No response; no relevant Very little Some evidence at level; partial explanations. Most Nearly all Some Merit level with remainder at is at Merit level with some at most tasks with evidence at Excellence level weak or incomplete. most tasks with evidence at Excellence level accurate and full. As above. 1a 2a 3a 1e + 1a 1m + 1a 4a 2m 1e + 2a 1e + 1m 3m 2(d) is correct 2(d) is correct including explanation of angle of incidence measured from normal and ray bends away more from plastic to air compared to bending towards normal from seawater to plastic

6 NCEA Level 1 Physics (90938) 2015 page 6 of 7 Q with Merit with Excellence THREE (a) One correct ray drawn, Correct ray diagram drawn, Or a correct ray diagram with two rays drawn but missing arrows, or no dotted lines for virtual rays. including arrows and dotted lines for virtual rays. (b) (c) A real image can be captured on a screen a real image is formed when real rays meet. A virtual image cannot be captured on a screen. Virtual image has diverging rays and a real image has converging rays States ONE of conditions: Light must travel from an optically denser medium towards an optically less dense medium. Light is incident at interface at an angle greater than critical angle. States BOTH conditions: Light must travel from water to air. / Light must travel from an optically denser medium towards an optically less dense medium. The incident light must strike (water-air) interface at an angle greater than critical angle.

7 NCEA Level 1 Physics (90938) 2015 page 7 of 7 (d)(i) Correctly calculates f: f = 1 T = 6 = 0.5 Hz 12 Correctly calculates v: v = d t = 15 = 0.50 m s 1 30 Correct calculation of wavelength, λ = 1 but missing/incorrect units Correctly calculates λ f = 1 T = 6 = 0.50 Hz 12 v = d t = 15 = 0.50 m s 1 30 v = f λ λ = = 1.0 m (Correct units required for λ) Correctly calculates λ f = 1 T = 6 = 0.50 Hz 12 v = d t = 15 = 0.50 m s 1 30 v = f λ λ = = 1.0 m (Correct units required for λ) (ii) Wavelength decreases / halves. Since v = f λ, doubling frequency halves wavelength because velocity remains constant. If frequency is doubled number of waves produced per second are doubled so wavelength will halve frequency is number of waves per second. E7: Since v = f λ, doubling frequency halves wavelength E8: because velocity remains constant. E7: If frequency is doubled number of waves produced per second are doubled so wavelength will halve. E8: frequency is number of waves per second. NØ N1 N2 A3 A4 M5 M6 E7 E8 No response; no relevant Very little Some evidence at level; partial explanations. Most Nearly all Some Merit level with remainder at is at Merit level with some at most tasks with evidence at Excellence level weak or incomplete. most tasks with evidence at Excellence level accurate and full. As above. 1a 2a 3a 1e + 1a 1m + 1a 4a 2m 1e + 2a 1e + 1m 3m 3(d) is correct 3(d) is correct including explanation that velocity remains constant and reference to v = f λ, Cut Scores Not Achieved with Merit with Excellence