You can test a relay with and without a 9 volt battery. If you apply 9 volts to it and it's sufficient to turn on the relay, the NO switch will close and then have continuity with common. If you don't apply voltage, the NO switch will be open and not have continuity with common. You can use these continuity and resistance checks to test a relay to see if it works.
Current I = V/R V = 9V R = 100ohm I = 9V/100ohm = 90mA
Sure. But not much water, a 9 volt battery has very little power (energy).
0.81 APEX
A "D-size" carbon-zinc cell at 100 mA would have about ten times as much "energy" as a 9V carbon-zinc at 8mA. A battery in the AAA series would have about the same energy as a 9V, which should not be surprising since a D is 10 time larger than a AAA.
no, if you charge 9 volt battery with 12 volt battery you will destroy 9 volt battery
best way to test a relay is remove it from board, get a 9v square battery and touch the switching terminals on the relay, the relay should click if its working. You can then test resistance through the relay. You can also check the feed to the relay, if theres pwer to the switching terminals on the relay, chances are the switch it ok. If no voltage, switch or wiring.
no
A car battery has six cells each producing two volts. A 9v alkaline battery has six cells each producing 1.5 volts. There are some obvious differences, like that a car battery can put out hundreds of amps and a 9v alkaline can only put out hundreds of milliamps, a 9v battery weighs 45 grams versus 45 pounds for a car battery, and so on.
you better not. you need a 9V regulator for this, not a resistor!
No.
no
You can buy 9V batteries from almost any supermarket
very
use inverter
9v! More voltage, more strength! Many 9v batteries merely have 1.5Volt cells jammed together to make 9V!
No.
Current I = V/R V = 9V R = 100ohm I = 9V/100ohm = 90mA