Waves question Mark scheme
Q1.
(a)  increased
1
(b)  (count) how many waves pass a point
1
in one second
this is dependent on the first mark point being awarded
1
or
(count) number of waves that pass a point in a given time
allow a specific time for a given time
or
(count) number of waves that are produced in a given time (1)
and divide by that time in seconds
this is dependent on the first mark point being awarded
allow an answer in terms of measuring the frequency of the vibrating bar
(c)  
1
period = 0.2
1
seconds / s
1
[6]
Q2.
(a)     sound
1
(b)     (visible) light
1
(c)     cooking food
1
(d)     1.2 gigahertz
1
(e)      300 000 × 1000 = 300 000 000 m/s
1
(f)     wave speed = frequency × wavelength
allow v = f λ
1
(g)     300 000 000 = 1200 000 000 × λ
an answer of 0.25 scores 3 marks
1
 
allow ecf from (e)
1
λ = 0.25 (m)                                                1
[10]
Q3.
(a)     K
1
(b)     Decreases
1
(c)     use a metre rule / 30 cm ruler to measure across 10 (projected) waves
accept any practical number of waves number for 10
1
and then divide by 10
1
(d)     1.2 cm = 0.012 m
1
18.5 × 0.012 = 0.22(2) (m / s)
1
allow 0.22(2) with no working shown for 2 marks
typical walking speed = 1.5m / s
accept any value e.g. in the range 0.7 to 2.0 m / s
1
so the water waves are slower (than a typical walking speed)
this cannot score on its own
1
[8]
Q4.          (a)    (wave) B  
             (the parts of the) spring oscillate / move back and forth in direction of / parallel to wave      
             travel OR mention of compressions and rarefactions  
             Second mark can only be scored if first mark is scored 2 
(b)     (i)     (double ended arrow / line / brackets) from between two points in phase  1 
(ii)     wave A: arrow vertically upwards  
        wave B: arrow horizontally to the left     2 
(c)     (transmitted radio waves are often) polarised  
       aerial (rods) must be aligned in the same plane (of polarisation / electric field) of the wave  2 
                                                                                                 [7]
Qu5  (a)     (i)      0.4(0) m (1) 
              (ii)     speed ( = frequency × wavelength) = 22 × 0.4(0) ecf (1) = 8.8 (m s–1) (1)