The light must be either very dim or else non-existent.
We can't see the light wave or the label.
Answer:
b.
Explanation: I do not know much about this but the answer that i think it is was b.
Maybe this will help you out:
Momentum is calculate by the formula:

Where:
P = momentum
m = mass
v = velocity
The SI unit:

So the unit of momentum would be:

Impulse is defined as the change in momentum or how much force changes momentum. It can be calculate with the formula:
I = FΔt
where:
I = impulse
F = Force
Δt = change in time
The SI unit:
F = Newtons (N) or 
t = Seconds (s)
So the unit of impulse would be derived this way:
I = FΔt
I =
x 
or

You can then cancel out one s each from the numerator and denominator and you'll be left with:

So then:
Momentum: Impulse

Answer:
Explanation:
Its definitely an Attractive force since the two charges are Unlike.
From Coulombs Law
F=kq1q2/R²
Given
K=9x10^9
R=1m
q1=2C
q2=-1C
F=(9x10^9 x 2 x -1)/1²
F= - 1.8x10^10N. (Attractive).