I believe the answer is the first one.
Answer:
1. The magnetic field encircles the wire in a counterclockwise direction
Explanation:
When we have a current carrying wire perpendicular to the screen in which the current flows out of the screen then by the Maxwell's right-hand thumb rule we place the thumb of our right hand in the direction of the current and curl the remaining fingers around the wire, these curled fingers denote the direction of the magnetic field which is in the counter-clock wise direction.
Ever current carrying conductor produces a magnetic field around it.
Acceleration (magnitude anyway) = (change in speed) / (time for the change) .
Change in speed = (10 - 30) = -20 m/s
Time for the change = 4.0sec
Magnitude of acceleration = -20/4 = <em>-5 m/s² </em>
Rarefraction.
Crest- tallest spot on transverse wave.
Trough- shortest point on transverse wave.
Compression - spot on a compressional wave where the waves are closer together.
Rarefraction - spot on a compressional wave where the waves are farther apart.