Question

two uses of solenoid

Answer 1

Electromagnetic solenoids find uses all over the world.

They're in hotel door locks, water-pressure valves in air conditioning systems, MRI machines, hard disk drives, speakers, microphones, power plants, and cars.

You can hardly swing a bat without hitting a solenoid.

Speakers and microphones, for example, both contain solenoids.

In fact, a speaker and microphone are pretty much exactly the same thing in reverse of each other. 

Answer 2

Electromagnets, inductors, etc