The two different isotopes have weights :
w1 = 78.918 amu
w2 = 80.916 amu
average weight w3 = 79.903 amu
The mixing of two components can be modeled as
let the fraction of w1 be 'x'
hence
now this is a linear equation in 'x'. Substituting the values we get
x = 0.507
hence the percentage of Br79 = 50.7% and the percentage of BR81 = 49.3%
Answer:
steady state temperature =88.7deg C
t=time within 1 deg C of it steady state is 8.31s
Explanation:
A 1 m long wire of diameter 1mm is submerged in an oil bath of temperature 25-degC. The wire has an electrical resistance per unit length of 0.01 Ω/m. If a current of 100 A flows through the wire and the convection coefficient is 500W/m2K, what is the steady state temperature of the wire? From the time the current is applied, how long does it take for the wire to reach a temperature within 1-degC of the steady state value? The density of the wire is 8,000kg/m3, its heat capacity is 500 J/kgK and its thermal condu
The diameter of the wire is known to be=1mm
properties=
The density of the wire is 8,000 kg/m3,
heat capacity is 500 J/kgK
themal conductivity is 20W/m.K
electrical resistance per unit length of 0.01 Ω/m
from lump capavity method
500*(2.5*10^-4)/20
0.006<0.1
we know also, to find steady state temperature
Dh(T-Tinf)=
make T the subject of the equation , we have
T=25+
T=88.7 degC
rate of chnage in temperature
dT/dt=
at t=o and integrating both sides
we have
t=8.31s
steady state temperature =88.7deg C
t=time within 1 degC of it steady stae is 8.31s