# Joule's Law - HP -22S Owner's Manual

Scientific calculator.

. 1
UNITS ! {L} {~CM}
R?1,4967E13
0100
I
INPUT!
R=
149,668,992,000.
F=3,4525E22
Converts inches to
centimeters.
Stores R, calculates F.
Example: Coulomb's Law.
Calculate the force of attraction between
an electron (charge = -1.6022 x 10
-19
C)
and an alpha particle
that are 2 angstroms apart.
(An
alpha particle is positively charged;
the magnitude of the charge is twice that of an electron. 1 angstrom
= 10-
10
m.)
Keys:
Display:
Description:
I
EVAL!
K?value
Prompts for the
constant.
8.98756
.m
9
I
INPUT !
A?value
Stores
K,
prompts for
electron's charge.
1.6022
ElJ.m
B
19
Stores
A,
prompts for
I
INPUT!
B?value
alpha particle's charge.
I
RCL!
A
ElJ
Calculates alpha
o
211NPUTI
B=3.2044E-19
particle's charge, stores
R?value
value in B.
2
.m
B
10
I
INPUT !
F=-1.1536E-8
Stores R (meters), cal-
culates F.
Joule's Law
The equation for Joule's Law is:
where
I
=
p=
R=
P=!"2xR
the current (in amperes).
the power (in watts).
the resistance (in ohms).
7: The Equation Library
99