When we "ON" AirDrop, the bluetooth is automatically switch "ON", but when we turnoff AirDrop, the bluetooth is not turned off.
iPhone 5, iOS 7
When Bluetooth is on and not connected it uses very little power as described earlier. As Ralph9430 said, you can turn it off in Control Center.
If you would like to tell Apple it should be turned off when turnign AirDrop off, let them know here, www.apple.com/feedback and click on the appropriate link.
Airdrop uses Bluetooth to make the initial connection then switches to Wi-Fi to complete the file transfer. That's why Bluetooth comes on when you turn on airdrop. Bluetooth, when in listening mode and not being used, uses so little power it isn't necessary to turn it off. But if you want it off, after turning off airdrop, tap the Bluetooth icon to turn off Bluetooth.
I dont know that it will be taking little power. But they(apple developers) might have made it as OFF, when we switch off AirDrop.
Perhaps. But I keep Bluetooth on all the time to enable connection to other devices. I would not want my Bluetooth turned off when and if I turned off AirDrop.
AirDrop vs Bluetooth
