Answer:
The correct answer is option 'B': Load is far from fulcrum and the effort is applied near the fulcrum
Explanation:
A lever works on the principle of balancing of torques. The torque about the fulcrum by the load should be equal to the torque by the applied effort. Since we know that the torque is proportional to both the force and the distance it is applied from the distance from the axis of rotation. A lever is used when we need to lift a heavy load by utilizing this effect of the lever arm.
A mechanical disadvantage occurs when we are not able to lift the weight easily due to the fact we apply effort near the fulcrum.
Answer:
A selective surface with large absorption for solar radiation and high reflectance for thermal infrared radiation was produced by use of surface oxidation of stainless steel. The surfaces were studied for use with concentrated light in a solar power plant at temperatures of 400°C and higher.
In order to investigate the relation between surface treatment and optical properties, stainless steels (AISI 304 and 430) which were submitted to different chemical and mechanical surface treatments, were used. To increase the spectral selectivity, these surfaces were treated in air and in vacuum at different temperatures and times. The optical properties of these films were investigated. Visual and infrared spectral absorptances were measured at room temperature. The thermal hemispherical emittance and absorptance were obtained by a calorimetric method at 200°C. It was noticed that these chemically and mechanically treated stainless steel surfaces have good spectral properties without further oxidations. This is very important for high temperature uses. The best values are found for samples 7 and 8 under vacuum and air. These two samples with mechanically ground surfaces retained their selectivity and specularity after several hours oxidation. One can conclude that the surface ground treatment confers good selectivity on the steel surfaces for use in concentrating solar collectors with a working temperature of 500°C.
Sample surfaces were subjected to long temperature ageing tests in order to gain some idea of the thermal stability of the surfaces. The results promise better-performing surface and the production of durable selective finishes at, possibly, lower cost than competing processes.
Explanation:
Answer:
Explanation:
When white is inside a , there's not enough air inside the to cause the water to
to make the sticky. Basically, the protects the from the air and keeps the runny.
Answer:
its so simple. u must mind some formulas.
Explanation:
mili->10^(-3)
micro->10^(-6)
nano->10^(-9)
so write the exact number and move "." to left or right depend question.
in this one:
23.5 is 23500000.0 nano with a default dot at the end
for turning to mili u must move the dot 6 steps to left so it will be: 23.5 milimeter.
