Thank you for posting your question here at brainly. Below is Yoland's study:
<span>Yolanda is studying two waves. The first wave has an amplitude of 2 m, and the second has an amplitude of 3 m.
</span>
I think the answer is "She can use constructive interference to generate a wave with an amplitude of 1.5 m."
Electricity is NOT a part of electromagnetic spectrum.
An electromagnetic spectrum contains electromagnetic radiations arranged according to frequencies and wavelength.
<h2>Further Explanation
</h2><h3>Electromagnetic waves </h3>
- Electromagnetic waves are types of waves that do not require a material medium for transmission.
- These waves are mostly transverse in nature, which means the direction of transmission is perpendicular to the direction of vibration of particles.
- They include, light waves, radio waves, x-rays, infra-red, etc.
<h3>Electromagnetic spectrum
</h3>
- An electromagnetic wave shows electromagnetic waves arranged according to frequencies and wavelength.
- Electromagnetic spectrum contains electromagnetic waves: Gamma rays, x-rays, Ultraviolet, Visible light, infra-red, microwaves, and radio waves.
- The electromagnetic spectrum is divided into various sections based on wavelength, with gamma rays having the shortest wavelength and radio waves having the longest wavelength.
- The part of the electromagnetic spectrum that we can see using our naked eyes is called the visible light spectrum.
- In order of frequency, the radio waves have the lowest frequency while gamma rays have the largest frequency.
<h3>General characteristics of electromagnetic waves </h3>
- They travel with the speed of light (3.0 x 10^8 m/s)
- They possess energy that is given by; E =hf, where h is the plank’s constant and f is the frequency.
- They are transverse in nature, and therefore, the wavelength is measured between successful crests or troughs.
- They can travel through vacuum
Keywords: Electromagnetic spectrum, electromagnetic waves.
<h3>Learn more about: </h3>
Level: High school
Subject: Physics
Topic: Electromagnetic spectrum
Answer:

Explanation:
The original equation is:

We notice that:
- we have 1 atom of Fe on the left, and 2 atoms of Fe on the right
- we have 2 atoms of O on the left, and 3 atoms of O on the right
Therefore, the equation is not balanced.
In order to balance it, we can add:
- a coefficient 3 in front of 
- a coefficient 2 in front of 
So we have:

Now the oxygen is balanced, but the iron it not balanced yet, since we have 1 Fe on the left and 4 on the right. Therefore, we should add a coefficient 4 on the Fe on the left:

For number one she is going to observe the contraction of the ballon
For number two she is going to observe the expansion of the ballon