The three longest wavelengths for the standing waves on a 264-cm long string that is fixed at both ends are:
- 5.2 meters.
- 2.6 meters.
- 1.7meters.
Given data:
Length of the fixed string = 264cms = 2.64 meters 
The wavelength for standing waves is given by: 
λ = 2L/n
where,
- λ is the wavelength 
- L is the length of the string
For n = 1,
 = 5.2 meters 
For n = 2,
 = 2.6 meters 
For n = 3,
 = 1.7 meters 
To learn more about standing waves: brainly.com/question/14151246
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Answer:
The electron microscopes  are uses the electron to produce the image of the any object.The area where the electron passes then that area  appeaser white but on the other hand where the electron does not pass that area appears black.But this does not give any information about the color of light it shows only white and black areas.We also know that color is the property of photons ( light).So the microscopes does not produce color of the image.
 
        
             
        
        
        
#3, they both come after infared and are not harmful to living cells.
        
             
        
        
        
Answer:
3.7 m/s
Explanation:
M = 444 kg 
U = 5 m/s 
m = 344 kg 
u = - 5 m/s 
Let the velocity of train is V and the car s v after the collision. 
As the collision is elastic 
By use of conservation of momentum 
MU + mu = MV + mv 
444 x 5 - 344 x 5 = 444 V + 344 v 
500 = 444 V + 344 v 
125 = 111 V + 86 v .... (1) 
By using the formula of coefficient of restitution ( e = 1 for elastic collision)

-5 - 5 = V - v 
V - v = - 10 
v = V + 10 
Substitute the value of v in equation (1) 
125 = 111 V + 86 (V + 10) 
125 = 197 V + 860 
197 V = - 735 
V = - 3.7 m/s 
Thus, the speed of first car after collision is 3.7 m/s. negative sign shows that the direction is reverse as before the collision. 
 
        
             
        
        
        
The answer is D. the way I remember it is they all end with -alism.