Final answer:
In a direct operating, electric actuator, (b) the plunger is connected directly to the disc of a globe valve, which provides immediate and precise control. A solenoid generates a magnetic field when electrified, and change in this field induces forces and emf in nearby conductors, a principle used in various applications.
Step-by-step explanation:
In a direct operating, electric actuator:
- (b) the plunger is connected directly to the disc of a globe valve
This statement means that the movement of the plunger, which is typically driven by an electric current flowing through a solenoid, directly translates to the opening or closing of a valve.
This type of mechanism eliminates the need for intermediate mechanical linkages, allowing for a more immediate and precise control of the valve's position. An electric actuator can be used in various control systems, including industrial process control or automation applications.
In the context of a solenoid and its applications:
- A solenoid is a uniform cylindrical coil of wire that becomes magnetized when an electric current passes through it, generating a magnetic field.
- When this magnetic field changes, such as when the current is turned on or off, it can induce an electromotive force (emf) in nearby conductive materials according to Faraday's and Lenz's laws.
- This phenomenon explains events like the jumping ring, where the induced emf and the resultant magnetic field force can cause the ring to leap into the air.
Understanding the interplay between electric currents, magnetic fields, and induced forces is crucial in designing and operating electric actuators and other electromagnetic devices. Option b) is the correct one.