Answer:
The magnetic field strength is 3.9 x 10⁻³ T
Explanation:
The equation for the magnetic field strength produced by a long straight current-carrying wire is written as;

Where;
μ₀ is constant = 4π x 10⁻⁷ N/A
I is the maximum current = 20 A
r is the radius of the wire = 2.053/2 = 1.0265 mm = 1.0265 x 10⁻³ m
Substitute in this values into the equation above;

Therefore, the magnetic field strength is 3.9 x 10⁻³ T
When light crosses the boundary between layers with different densities, the light is refracted. (A).
(C)
Explanation:
The circle has a radius r = 0.5 m, which means that its circumference C is

One revolution means that the stopper travels a distance equal to the circumference of the circle so the velocity of the stopper is
