Answer:
Wavelength is calculated as 213.9 nm
Solution:
As per the question:
Wavelength of light = 570 nm
Time, t = 16.5 ns
Thickness of glass slab, d = 0.865 ns
Time taken to travel from laser to the photocell, t' = 21.3
Speed of light in vacuum, c = 
Now,
To calculate the wavelength of light inside the glass:
After the insertion of the glass slab into the beam, the extra time taken by light to cover a thickness t = 0.865 m is:
t' - t = 21.3 - 16.5 = 4.8 ns
Thus


where
n = refractive index of the medium
v = speed of light in medium


n = 2.66
Now, 
The wavelength in the glass:


 
        
             
        
        
        
Answer:
 7.89 7.91 
Explanation:
The ranges of measurement lie between 7.92-0.05 and 7.92+0.05
7.87g and 7.97g
 
        
                    
             
        
        
        
Answer:
 6.39 J of energy is needed to generate 0.71 * 10⁻¹⁶ kg mass
Explanation:
According to the Equation: E = mc²
where the mass, m = 0.71 * 10⁻¹⁶ kg
the speed of light, c = 3 * 10⁸ m/s
The amount of energy needed to generate a mass of 0.71 * 10⁻¹⁶ kg is calculated as follows:
E = (0.71 * 10⁻¹⁶) (3 * 10⁸)²
E = 0.71 * 10⁻¹⁶ * 9 * 10¹⁶
E = 0.71 * 9
E = 6.39 J
 
        
             
        
        
        
Answer:
 12m
Explanation:
Given parameters: 
Distance walked westward  = 2.8m 
Time of travel  = 5min 
Distance walked eastward = 9.2m 
Time of travel  = 10min 
Unknown: 
The total shopper's travel distance  = ? 
Solution: 
Total distance traveled is the sum of the length of path covered by a body. It is a scalar quantity. 
  Total distance = distance walked westward + distance walked eastward 
   Total distance  = 2.8m + 9.2m  = 12m