Explanation:
Lasers produce a narrow beam of light in which all of the light waves have very similar wavelengths. The laser's light waves travel together with their peaks all lined up, or in phase. This is why laser beams are very narrow, very bright, and can be focused into a very tiny spot.
Acrostic poem is a poem where the initials of the main word is given a respective sentence starting with that initial.
C- Can you see any changes happened in our surrounding?
L- Let me open your eyes and wake up to the reality.
I- Ignoring the unprecedented changes in our environment is worsening.
M- Making a move? Let's start it now.
A- Another day might not come.
T- Take this opportunity to show to world that we care.
E- Even to smallest thing that we can share.
Answer:

Explanation:
A simple pendulum is a system consisting of a mass attached to a string, and oscillating in a periodic motion, back and forth, along an equilibrium position.
The period of a pendulum is the time it takes for the pendulum to complete one oscillation.
The period of a pendulum is given by the equation

where
L is the length of the pendulum
g is the acceleration due to gravity
From the formula, we see that the period of a pendulum does not depend on the mass.
Therefore, the only 2 factors affecting the period of a pendulum are:
- The length of the pendulum: the longer it is, the longer the period of oscillation
- The acceleration due to gravity: the greater it is, the shorter the period of the pendulum
<span>speed = wavelength x frequency
speed = 0.4m X 10 Hz
speed = 4 m/s</span>