Aclosed box is filled with dry ice at a temperature of -87.1°c, while the outside temperature is 17.6°c. the box is cubical, measuring 0.332 m on a side, and the thickness of the walls is 4.41 × 10^-2 m. in one day, 3.34 × 10^6 j of heat is conducted through the six walls. find the thermal conductivity of the material from which the box is made.

K=24.17 x 10⁻² J s⁻¹c⁻¹m⁻¹

Explanation:

Rate of flow of heat through a material is given by the following expression

where Q is amount of heat flowing in time t through area A and  a medium of thickness d having two faces at temperature difference δT . K is thermal conductivity of the medium .

Here Q = 3.34 x 10⁶/6 , t = 24 x 60 x 60 = 86400 s , A = .332 X .332 = .0110224 m² ,  δT = 104.7

Put these values here

K=24.17 x 10⁻² J s⁻¹c⁻¹m⁻¹

emily ruth's annual premium is $1058.50

step-by-step explanation:

emily ruth is a female of 27 years age purchasing 20 year endowment insurance with face value $25000.

from the given table,

for females, the age of a male 3 years younger should be used.

so, we have to check for 24 year male for 20 year endowment.

it is 42.34 for every $1000 face value.

for a face value of $25000,

it is 25 * 42.34 = $1058.50

∴ emily ruth's annual premium is $1058.50

answer: 2×10^-2kg

explanation: density= mass per volume

vol=mass/density

converting to s.i units we have;

3÷1000kg = 0.003

1.5÷100m = 0.15

0.003/0.15 = 0.02kg