In most of leaves the upper surface will be more green and shiny than the lower surface. Why?

Most leaves have the upper surface more green and shiny than the lower ones. Why?

A steel plate of face area 2 cm^(2) and the thickness 1.0cm is fixed at the lower face. A tangential force of 10N is applied on the upper surface. Find the lateral displacement of the upper surface with respect to the lower surface. Rigidity modulus of steel =8.4xx10^(10)Nm^(-2)

A parallel beam of light of intensity I_@ is incident on a coated glass plate. If 25% of the incident light is reflected from the upper surface and 50% of light is reflected from the lower surface of the glass plate, the ratio of maximum to minimum intensity in the interference region of the reflected light is

A fully loaded boeing aircraft has a mass of 3.3 times 10^5 Kg . Its total wing area is 500 m^2 . It is in level flight with a speed of 960 km//h (a) Estimate the pressure difference between the lower and upper surfaces of the wings (b) Estimate the fractional increase in the speed of the air on the surface of the wing relative to the lower surface.[ The density of air is p= 1.2 kg m^-3 ]