(3) The decay rate also may be calculated from the plotted slope by measuring each axis and

*y*

using the formula *n *=

.

*x*

(a) To do this, measure the distance from the point where the "best fit" line crosses the

y-axis directly down to the bottom of the log-log cycles. Record this measurement as the *y *. Measure

from the point where the best fit line crosses the x-axis directly to the left edge of the log-log-cycles.

Record this measurement as the *x *. See the example measurements for locations A and B in Figure 4-5.

100

90

80

LOCATION C

70

60

50

40

A

128

LOCATION A

mm

y

C1

20

39mm

X

C

10

35mm

9

B

8

89mm

7

LOCATION B

6

5

4

A 107mm

B 87mm2.0

0.3

0.5

1.0

4.0

6.0

7.0

x axis

Time after burst (H + ___ hours)