Assessed homework

1.       (a)     (i)      B;                                                                                                            1

(ii)     A;                                                                                                            1

(b)     Hz;                                                                                                                   1

  (c)    (i)      An explanation to include:

1. ripples are transverse waves;
2. (movement) displacement only in the vertical plane;                 2

  (ii)   energy;                                                                                                    1

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  2.     (a)     4 (cm);
[accept 0.04 m]                                                                                                1

  (b)   3                                                                                                                       1

  (c)   ripples at 90 degrees / vertical displacement (up / down);
to wave travel / not forward and back;                                                             2

  (d)   Any two valid types of transverse waves, for example:

          1.    light waves;
2.    radio waves;
3.    ‘S’ waves;
4.    micro waves;
5.    γ rays;
6.    TV waves;
7.    ultraviolet waves;
8.    infra red waves;
9.    vibrating string / rope;
10.  slinky in right direction;                                                                   2

          [em wave – 1 mark
no further mark for named em wave,
for example
em waves
infra red
will score 1 mark only]

[Reject water ripples on water / tidal]

  (e)   correct position shown including line;                                                              1
[Allow reasonable tolerance]

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  3.     (a)     change of direction / speed of light in a new medium / OWTTE;
(ignore bending)                                                                                               1

  (b)   greater refraction shown at P;
emergent ray shows greater refraction;
(these marks are independent)                                                                          2

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4.       (a)     A calculation to include:

          1. v    =        f  ´ l;
2.       =        200 000 Hz ´ 1500 m;
3.       =        300 000 000 m/s;
[Accept 200 Hz ´ 1500 m = 300 000 m/s for 2 marks]
[Allow 300 000 for 1 mark (i.e. no unit)]                                                3

  (b)   C;                                                                                                                     1

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  5.     (a)     four or five points plotted correctly                                                                  2

Allow 1 mark for two or three points plotted correctly
curve drawn;                                                                                                    1

  (b)   decreases                                                                                                          1

(c)      (i)      1.2 m ;                                                                                                     1

(ii)     speed = frequency × wavelength

= 1250 Hz × 1.2 m;

= 1 500 m/s                                                                                    3

          Allow full marks for a correct calculation based on an incorrect answer to (c)(i)

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  6.    

All four correct - 3 marks

three/two correct - 2 marks

one correct - 1 mark

[3]

 

  7.     (i)      microwave;                                                                                                       1

(ii)     ultraviolet;                                                                                                        1

(iii)    cell damage / cancer / sterility / damage to unborn babies;                               1

  (iv)  Any two from:

1.  transverse;

2.  same speed (in vacuum);

3.  travels in a vacuum;                                                                       2

          [Accept any correct wave property]

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