A long solenoid has 500 turns. When a current of 2 amperes is passed through it, the resulting magnetic flux linked with each turn of the solenoid is 4×10-3 Web. The self-inductance of the solenoid is (1) 1.0 henry (2) 4.0 henry (3) 2.5 henry (4) 2.0 henry
Answer: (1) 1.0 henry
A solenoid is a coil of wire tied across a piston, mostly made of iron, in the form of a corkscrew.
- Like with all electromagnets, when an electric current passes via the wire a magnetic field is generated.
- The magnetic field of an activated solenoid has both positive and negative poles that attract or repel sensitive material to the magnets.
- The electrical force causes the piston to shift either forward or backward inside a solenoid that’s how a solenoid coil creates motion.
- Number of turns = 500
- Current (I) = 2A
Flux linkage = Flux through each number of turns
ϕ = 500 × 4 × 10-3
ϕ = 2Wb
Since ϕ = LI
L = ϕ /I
L = 2/2
L = 1 H