The law is effective immediately.
A decline in the effective demand.
An example of effective is a good solid argument that lets you convince others of your point.
The pill is an effective method of birth control.
The president delivered an effective speech!
Gave an effective performance as Othello.
How long does it take to make a bunch of civilians an effective military force?
My effective income after taxes and child support is $500 a month.
The effective radiated power is determined by multiplying the transmitter power output with the antenna gain.
The effective voltage of an alternating current is 0.7 times its peak voltage.
The curfew is effective at midnight.