My Samsung mobile is dead after it slipped and fell momentarily in water. What could be the possible cause ???

It sounds like it did an emergency stop. any beeps or flash codes.

Check your user manual for possible causes.

If the batteries do go flat, they get to a certain voltage level and the scooter cuts out for safety reasons.

Put it in a Tupperware container with rice in it for a week. Remove the battery if you can.

it can be fixed on mobile shops

remove all possible [parts, battery, back cover, sim card, memory card and other things you can open using a special screw driver, let it dry several days or use a hair dryer on cool settings until determined everything is dry.

As for the battery, let is dry under the hot sun before attempting to put it back in the phone.

after that make a simple power on test, if it works, you are in luck, otherwise consider your phone completely water damaged and will not be accepted for repair due to the red water damage mark indicator.

my nokia 110 fell in water and dead

Possible that the water has seeped in and if the battery is within the unit then it could have caused damage to the mobile hardware.
Check this link : Tips to clean :

Hey!
Well I am sorry but phones aren't waterproof! You might be able to send it to Samsung but theres a chance its gone forever
Hope this helps!

i forgot password of mobile

only by a qualified engineer yes.

The following method can be tried when everything else failed and the phone went through the washing machine, fell in salt water or was in dirty water for a long time etc.

Remove as many parts as possible (Sim card, covers, battery)

1. Soak the phone as soon as possible in distilled water to dissolve any dirt, salt, soap etc ( an ultasonic cleaner will be helpful )

2. Repeat step 1 if necessary ( depends how dirty the water was )

3. Soak the phone in Iso Propyl Alcohol ( a very short time in an ultasonic cleaner will be helpful to dissolve the distilled water in the alcohol )

4. Let the phone dry thoroughly,

5. Cross your fingers and switch it on.