Answer Explanation:
the efficiency of the the engine is given by=1-
where T₂= lower temperature 
            T₁= Higher temperature
we have given efficiency =70%
lower temperature T₂=27°C=273+27=300K
higher temperature T₁=627°C=273+627=900K
efficiency=1-
                 =1-
                  =1-0.3333
                  =0.6666
                  =66%
66% is less than 70% so so inventor claim is wrong
 
        
             
        
        
        
Answer:
Among the different types of excavation protection system, as a way of preventing accidents against cave-ins, the sloping involves cutting back the trench wall at an angle inclined away from the excavation. Shoring requires installing aluminum hydraulic or other types of supports to prevent soil movement and cave-ins. Shielding protects workers by using trench boxes or other types of supports to prevent soil cave-ins (OSHA). In addition, the regulations do not allow employees to work on excavations where there is an accumulation of water. If this occurs, water on the site must be constantly removed by suitable equipment preventing water from accumulating. The entry of surface water into the excavations must also be prevented by means of diversion ditches, dam, or other suitable means.  
Explanation:
 
        
             
        
        
        
Explanation:
1) Wind energy is generated through a wind turbine. When wind passes through the blades of wind mill, the blades of the wind mill tend to rotate. Due to the spinning of the rotor across the turbine, the kinetic energy from the wind is converted to electrical energy
2) Incase of wind energy, the consumption gets higher when there is more wind and would be zero incase of no movement of blades.
Incase of hydroelectric power, the generation is rather stable and consumption depends on the usage of power from the consumers
Incase of gasoline generator, the generation is also stable subject to availability of gasoline and consumption again depends on the usage of power from the consumers
3) Pros of Hydroelectric power
Cost of electricity generation is less
Can produce green energy
Produce mass volume of electricity
Cons of Hydroelectric power
Requires massive initial investement
Can be installed on certain demographical area