I'm not exactly sure but I'm thinking that it's the last one. Sorry if I'm wrong
        
                    
             
        
        
        
Because the specimen is very small with a light microscope
        
             
        
        
        
It's angle of reflection must be 41 degrees
we know, by the first law of reflection that angle of incidence is always equal to angle of reflection..........
 
        
                    
             
        
        
        
Answer:
(a) 37.5 kg 
(b) 4
Explanation:
Force, F = 150 N 
kinetic friction coefficient = 0.15 
(a) acceleration, a = 2.53 m/s^2 
According to the newton's second law 
Net force = mass x acceleration 
F - friction force = m a 
150 - 0.15 x m g = m a 
150 = m (2.53 + 0.15 x 9.8) 
m = 37.5 kg 
(b) As the block moves with the constant speed so the applied force becomes the friction force. 
 
 
        
             
        
        
        
Answer:
the magnitude of the charge Q on each plate is 
Explanation:
Given that :
mass (m) = 
charge (q) = +0.155 µC = 
angle 
Area A on each plate = 0.0135 m²
From the diagram below; 
 ----- equation (1)
    ----- equation (1)
Also by using Gauss Law ;

 ----- equation (2)
     ----- equation (2)
Combination equation 1 and 2 together ; we have 


