DP Physics (last assessment 2024)

Test builder »

Question 19N.2.SL.TZ0.6

Select a Test
Date November 2019 Marks available [Maximum mark: 4] Reference code 19N.2.SL.TZ0.6
Level SL Paper 2 Time zone TZ0
Command term Determine, Suggest Question number 6 Adapted from N/A
6.
[Maximum mark: 4]
19N.2.SL.TZ0.6

Wind is incident on the blades of a wind turbine. The radius of the blades is 12 m. The following data are available for the air immediately before and after impact with the blades.

(a)

Determine the maximum power that can be extracted from the wind by this turbine.

[3]

Markscheme

P=12×A×1.2×83 OR P=12×A×1.32×43  ✔

P «in incoming beam» = 1.4×105 «W»
OR
P «in outgoing beam» = 1.9×104 «W» ✔

subtracts both P to obtain 1.2×105 «W» ✔

NOTE: Condone use of a wrong area or use of circumference in MP1.
Allow ECF from MP2.
Award [1] max for any attempt to use the formula for wind power which cubes the difference of velocities
Award [3] for a bald correct answer

 

(b)

Suggest why the answer in (a) is a maximum.

[1]

Markscheme

because some power is lost due to inefficiencies in the system/transfers to the surroundings ✔

NOTE: Accept power or energy indistinctly

Syllabus sections