Quelpr
13 marksSI Units

CAPE Physics Unit 1 · 1999 · Paper 2 · Question 5(b)(i)

In an experiment, the viscosity, η, of a liquid is determined in terms of the volume, v, passing per second through a capillary tube of radius, r, and length, l, under a pressure difference, p, where η = πpr⁴ / (8lv).

Assuming the given equation to be homogeneous, show that the SI unit of η is N s m⁻².

The mark scheme is shown once you've answered.

Practise this question

Other parts of this question

  1. 5(a)(i)Three important 'base quantities' are mass, length and time. Explain the term 'base quantity' and give another example of a 'base quantity'.[7 marks]
  2. 5(a)(ii)If in another system of units the base quantities and units are mass/kg, length/m, and force/N, what would be the unit of time?[1 mark]
  3. 5(a)(iii)How would you use base quantities or units to check the homogeneity of physical equations? State ONE way in which an equation that is homogeneous may,…[1 mark]
  4. 5(b)(ii)Estimate the uncertainty to which η can be determined.[1 mark]
  5. 5(b)(iii)What is the actual uncertainty in the measurement?[1 mark]
  6. 5(b)(iv)Identify ONE case of random error and one case of systematic error in the measurements of the physical quantities required to determine η. Say what you would…[1 mark]

More practice: the rest of this paper · more SI Units questions · all CAPE Physics Unit 1 past papers