You would like to freeze a surgically removed 5.0 cm diameter spherical brain tumor. in order to avoid the formation of large ice crystals within the tumor, you would like to keep the temperature within the tumor spatially uniform. tissue properties: constant thermal conductivity = 0.64 w/m*k, thermal diffusivity = 2.5 x 10-7 m2/s. (a) determine an appropriate h in order to meet this criteria. (b) how long will the tumor take to freeze, i. e. reach 0°c, if placed in a -20°c freezer using the h found in part (a).

Acommon technique in analysis of scientific data is normalization. the purpose of normalizing data is to eliminate irrelevant constants that can obscure the salient features of the data. the goal of this experiment is to test the hypothesis that the flux of light decreases as the square of the distance from the source. in this case, the absolute value of the voltage measured by the photometer is irrelevant; only the relative value conveys useful information. suppose that in part 2.2.2 of the experiment, students obtain a signal value of 162 mv at a distance of 4 cm and a value of 86 mv at a distance of 5.7 cm. normalize the students' data to the value obtained at 4 cm. (divide the signal value by 162.) then calculate the theoretically expected (normalized) value at 5.7 cm.