9702/52/M/J/20: A student investigates how the viscous force in a liquid varies with temperature.
The student releases a ball from the surface of the liquid in a container. The ball falls as shown in
Fig. 2.1. The student determines the speed of the ball between P and Q and measures the thermodynamic
temperature T of the liquid.
Viscosity is a term used to describe the viscous forces acting in a liquid. Viscosity has the unit
pascal second (Pas). The viscosity η of the liquid is calculated from the speed of the ball. The experiment is repeated for the same liquid at different temperatures. It is suggested that η and T are related by the equation
\( \eta = He^{\frac{E}{kT}}\)
where E and H are constants and k is the Boltzmann constant.
May/June 2020 Paper 5 Variant 2 Questions 2 data analysis.
I am sorry but shouldn't the gradient be 0.18 because you have not taken into consideration the power of the axes?
ReplyDeleteif you refer the table given at 292K (viscosity is 12.3 x 10^-4)
ReplyDelete303K (viscosity is 9.8 x 10^-4)
so shouldn't viscosity at 273K (calculated in e) be around 10^-4 too
I think the mistake was not including factor of ten (10^-3) when you substitute values from x-axis to calculate gradient. Y-axis, don't have to include factor of 10.
ReplyDeleteViscosity value will be 17 x 10^-4 Pa s.
Yepp, correction have been added! :)
Delete