It slowly cools an hardens,eventually turning into igneous rock<span />
        
                    
             
        
        
        
Answer:
A. The particle model, because only high-energy frequencies of light  can remove electrons . 
Explanation:
Each photon of blue light has higher energy than each photon of red light has  . So when each photon strikes each electron , it gets ejected . But the photon of red light has not sufficient energy to eject electron . Once the photon of red light strikes the electron , the energy is wasted off . Energy of photon can not be accumulated . Thus photon behaves like particle . 
 
        
             
        
        
        
Answer:
20m/second
Explanation:
The reason the answer is 20m/second is because to find the speed of the ball  in this question you have to divide the distance over the time giving you the result of 20m/second
 
        
             
        
        
        
Answer:
 2.16×10⁻⁶ N
Explanation:
Applying,
F = kqq'/r² (coulomb's Law)....................... Equation 1
Where F = electrostatic force, k = coulomb's constant, q = charge on the styrofoam, q' = charge on the grain of salt, r = distance between the charges.
From the question,
Given: q = 0.002 mC = 2.0×10⁻⁶ C, q' = 0.03 nC = 3.0×10⁻¹¹ C, r = 0.5 m
Constant: k = 8.99×10⁹ Nm²/C²
Substitute these values into equation 1
F = (2.0×10⁻⁶)(3.0×10⁻¹¹)(8.99×10⁹)/0.5²
F = 2.16×10⁻⁶ N
 
        
             
        
        
        
The speed of the sound in the xenon is 178 m/s. And the right option is b 178 m/s
<h3 /><h3>What is speed?</h3>
Speed can be defined as the ratio of the total distance traveled by a body to the total time taken.
To calculate the speed of the sound in the xenon, we use the formula below.
 Formula:
- v = λf............. Equation 1
 
Where:
- v = Speed of the sound in xenon
 - f = Frequency
 - λ = Wavelength.
 
From the question,
Given:
- f = 440 Hz
 - λ = 40.4 cm = 0.404 m
 
Substitute the values above into equation 1
- v = 440(0.404)
 - v = 177.76 m/s.
 - v ≈ 178 m/s
 
Hence, The speed of the sound in the xenon is 178 m/s. And the right option is b 178 m/s
Learn more about speed here: brainly.com/question/4931057