Answer:
No concave lens cannot be used to make hand lens because in hand Lens we use convex lens so as to converge the rays of the light After refraction and helps to produce a magnified image of an object.
Hope it will help you :)❤
 
        
             
        
        
        
Answer:
The answer of the part (a) is v2 = 7.09 m/s
and the answer of the part (b) is vA1 = 5.25 m/s
Explanation:
Explanation of the both parts of answer  is in the following attachments
 
        
             
        
        
        
Answer:
The energy is 
(a) is correct option
Explanation:
Given that,
Energy = 4480 j
Weight of nitrogen = 20 g
Boil temperature = 77 K
Pressure = 1 atm
We need to calculate the internal energy
Using first law of thermodynamics


Put the value into the formula



We need to calculate the number of molecules in 20 g N₂
Using formula of number of molecules

Put the value into the formula


We need to calculate the energy
Using formula of energy

Put the value into the formula


Hence, The energy is 
 
        
             
        
        
        
Answer:
134r kgm^-1 or 1344 kg /m 
Explanation:
Momentum is is given by:
p=mv
Where:
p is momentum, m is mass in kg and v is velocity in ms−1
p=120kg×11.2 m/ s= 1344 kgms=1344kgm^−1
 
        
             
        
        
        
Answer:
time machine popularized the concept of time travel by mechanical means. Yes a long time ago, mahal