Answer:
c. (H-h/2) above the ground
Explanation:
The mirror must be at least half as tall as the alien, and its base must be located at half of the distance between the alien's eyes and the ground (assuming that the alien doesn't float or levitate). 
This question is about the Law of Reflection which states that the angle of reflection = angle of incidence. 
I attached an image that can help you understand the concept, although the alien is not included.
 
        
             
        
        
        
I would guess anything that is black? black absorbs there most light energy. that's is why a black car in the sun will always be hotter inside than a white car.
        
             
        
        
        
Answer:

Explanation:
We have given initial length of the steel guitar l = 1 m 
Cross sectional area 
Young's modulus 
Force F = 1500 N 
So stress 
We know that young's modulus 
So 

Now strain 


 
        
                    
             
        
        
        
Answer:
All electrons are negative(-) charged
 
        
             
        
        
        
The answer is λ₂ = 6.48 cm or  6.52 cm.
The out-of-tune guitar may have a wavelength between "6.48 cm" and "6.52 cm."
fb = |f2 − f1|
f₁ = 343/0.064
= 5276Hz
f₂ = 5276.9 Hz ± 17 Hz
f₂ = 5293.9 Hz or 5259.9 Hz
Now, calculating the possible wavelengths:
λ = 343/ 5259.9  or 343/ 5293.9
λ₂ = 6.48 cm or 6.52 cm
<h3>Why is beat frequency important?</h3>
When two waves with almost identical frequencies traveling in the same direction collide at a certain location, beats are produced. The opposing beneficial and harmful disruption causes the sound to alternatively be loud and weak whenever two sound waves with different frequencies reach your ear. This is referred to as beating.
The entire value of the frequency difference between the two waves is the beat frequency.
The following formula yields the beat frequency:
fb = |f2 − f1|
Learn more about beat frequency here:
brainly.com/question/14705053
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