Marconi Instruments TF 2502 Instruction Manual page 11

Transposing and simplifying, equation (1) gives
m
Example: From measurements,
it
is found that 1. 1 Wand Pm
=
1. 5 W
Hence from equation (2)
J
2 (1.5 - 1.1) 1
(JJ
m
=
x.
001o
1.1
85.5%
10
2501 (1)