Faraaidh of wudhu

Performing wudhu using a spray bottle

Q: 

1. If wuḍuʾ is performed using a spray bottle, is the wuḍuʾ valid? 

2. With regard to the obligatory (farḍ) parts of the body that must be washed in wuḍuʾ, is it necessary for two drops of water to fall from each hair and part of the skin, or is it sufficient for two drops to fall from the entire organ (e.g., the face), even if only two drops fall in total after spraying water?