A believe that’s called a reference point.
Answer:
option C
Explanation:
given,
Q = +3.2 x 10⁻¹⁹ C
E = 5.0 X 10⁵ V/m
B = 0.80 T
ion's acceleration is zero
when acceleration is zero the magnitude of both the forces becomes equal.
q E = q V B
v = 
v= 
v = 6.25 × 10⁵ m/s ≈ 6.3 × 10⁵ m/s
hence, the correct answer is option C
Dark energy is a theoretical repulsive energy that causes the acceleration to the expansion of the universe. Among the choices, the nearest answer would be D. Dark energy can also be defined as a new form of energy, that is a dynamic field that fills up space but has an effect opposite to that of normal energy.
Water that flows across the surface is called a;
Runoff
That's when rain has saturated the ground to the point it cant hold anymore and it runs over the surface.