**Answer:**

Grid

**Explanation:**

The number of electrons attaining the fluorescent light is regulated by the **grid **in a cathode ray tube.When the heater is supplied with current, it allows the electrons to emit from the cathode. Before approaching the anode the electrons pass through grid opening. The number of electrons attempting to reach the anode may also be regulated by managing the number of electrons passing through the grid.

**Answer:**

Amplitude

**Explanation:**

The amplitude is maximum height a wave is measured from its rest position.

**Answer: **The amplitude is 0. (assuming that the amplitude ot both initial waves is the same)

**Explanation:**

When two monochromatic light waves of the same wavelength and same amplitude undergo destructive interference, means that the peak of one of the waves coincides with the trough of the other, so the waves "cancel" each other in that point in space.

Then if two light waves undergo destructive interference, the amplitude of the resultant wave in that particular point is 0.

<span>A **chemical** property of matter describes its ability to change into different substances..</span>

**Answer:**

Vf = 23 m/s

**Explanation:**

First we need to find the distance covered by the motorcycle 2 when it passes motorcycle 1. Using the uniform speed equation for motorcycle 1:

s₁ = v₁t₁

where,

s₁ = distance covered by motorcycle 1 = ?

v₁ = speed of motorcycle 1 = 6.5 m/s

t₁ = time = 10 s

Therefore,

s₁ = (6.5 m/s)(10 s)

s₁ = 65 m

Now, for the distance covered by motorcycle 2 at the meeting point. Since, the motorcycle started 50 m ahead of motorcycle 2. Therefore,

s₂ = s₁ + 50 m

s₂ = 65 m + 50 m

s₂ = 115 m

Now, using second equation of motion for motorcycle 2:

s₂ = Vi t + (1/2)at²

where,

Vi = initial velocity of motorcycle 2 = 0 m/s

Therefore,

115 m = (0 m/s)(10 s) + (1/2)(a)(10 s)²

a = 230 m/100 s²

a = 2.3 m/s²

Now, using 1st equation of motion:

Vf = Vi + at

Vf = 0 m/s + (2.3 m/s²)(10 s)

Vf = 23 m/s