B !! Is the correct answer
Answer:
The direction of the magnetic field around the coil reverses. The force on the cone now pulls it back in. Repeatedly alternating the current direction makes the cone vibrate in and out. The cone vibrations cause pressure variations in the air, which are sound waves.
Explanation:So as it goes back and forth it makes a sound from the vibration.
Explanation:
Step1
Lehr is the long open or closed insulated space for glass manufacturing. Lehr must be large enough to keep the cooling of glass uniform. The function of Lehr is the same as an annealing process in metallurgy.
Step2
Lehr decrease the cooling and temperature variation in glass production. Uneven temperature creates the internal stress in the glass. Lehr reduces the internal stress in the glass product. So, the main purpose of the Lehr is to reduce the internal stress and keep the cooling uniform.
