Do you speak a little English cuz I can’t help you if a can’t understand you
Answer:
Magnitude of the magnetic field inside the solenoid near its centre is 1.293 x 10⁻³ T
Explanation:
Given;
number of turns of solenoid, N = 269 turn
length of the solenoid, L = 102 cm = 1.02 m
radius of the solenoid, r = 2.3 cm = 0.023 m
current in the solenoid, I = 3.9 A
Magnitude of the magnetic field inside the solenoid near its centre is calculated as;

Where;
μ₀ is permeability of free space = 4π x 10⁻⁷ m/A

Therefore, magnitude of the magnetic field inside the solenoid near its centre is 1.293 x 10⁻³ T
Instantaneous velocity is the velocity at a specific instant in time. I bet you are taking Honors Physics.
D. Destructive interference. An easy way to think about it is the waves are opposite each other, so they essentially cancel each other out, or make an effort to.
If there is no current in the wire .....the direction of magnetic field remains unchanged