Answer:
two places where thermal conduction takes place are gases and liquids, conduction is due to collisions of molecules during their random motion. Hence, the correct option is (C). Note: Though, the particle distances between gases are much more in comparison to solids and liquids, conduction slowly occurs in gases also
Explanation:
i hope it will help you 
 
        
             
        
        
        
The answer to your question is 5:7
        
             
        
        
        
<span>b. objects.
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Answer: V = 15 m/s
Explanation:
As  stationary speed gun emits a microwave beam at 2.10*10^10Hz. It reflects off a car and returns 1030 Hz higher. The observed frequency the car will be experiencing will be addition of the two frequency. That is,
F = 2.1 × 10^10 + 1030 = 2.100000103×10^10Hz
Using doppler effect formula 
F = C/ ( C - V) × f
Where 
F = observed frequency 
f = source frequency 
C = speed of light = 3×10^8
V = speed of the car
Substitute all the parameters into the formula 
2.100000103×10^10 = 3×10^8/(3×10^8 -V) × 2.1×10^10
2.100000103×10^10/2.1×10^10 = 3×108/(3×10^8 - V)
1.000000049 = 3×10^8/(3×10^8 - V)
Cross multiply 
300000014.7 - 1.000000049V = 3×10^8
Collect the like terms 
1.000000049V = 14.71429
Make V the subject of formula 
V = 14.71429/1.000000049
V = 14.7 m/s
The speed of the car is 15 m/s approximately