p42 015

background image

15. The Fermi-Dirac occupation probability is given by P

FD

= 1/

e

E/kT

+ 1

, and the Boltzmann occu-

pation probability is given by P

B

= e

E/kT

. L et f be the fractional difference. Then

f =

P

B

− P

FD

P

B

=

e

E/kT

1

e

E/kT

+ 1

e

E/kT

.

Using a common denominator and a little algebra yields

f =

e

E/kT

e

E/kT

+ 1

.

The solution for e

E/kT

is

e

E/kT

=

f

1

− f

.

We take the natural logarithm of both sides and solve for T . The result is

T =

E

k ln

f

1

− f

.

(a) Letting f equal 0.01, we evaluate the expression for T :

T =

(1.00 eV)(1.60

× 10

19

J/eV)

(1.38

× 10

23

J/K) ln

0.010

1

0.010

= 2.5 × 10

3

K .

(b) We set f equal to 0.10 and evaluate the expression for T :

T =

(1.00 eV)(1.60

× 10

19

J/eV)

(1.38

× 10

23

J/K) ln

0.10

1

0.10

= 5.3 × 10

3

K .


Document Outline


Wyszukiwarka

Podobne podstrony:
p42 015
p42 015
03 0000 015 02 Leczenie dystonii miesniowych toksyna botulinowa
p11 015
p03 015
p35 015
P22 015
p36 015
p42 002
p42 001
P24 015
A D 015
p42 039
p06 015
P27 015
I B 015
015 LS ka7
P32 015
015

więcej podobnych podstron