Two blocks (m = 0.5 kg and M = 4.5 kg) are arranged on a horizontal frictionless table as shown in figure. The coefficient of static friction between the two blocks is $${3 \over 7}$$. Then the maximum horizontal force that can be applied on the larger block so that the blocks move together is ___________ N. (Round off to the Nearest Integer) [Take g as 9.8 ms^$$-$$2]

If 2.5 $$\times$$ 10^$$-$$6 N average force is exerted by a light wave on a non-reflecting surface of 30 cm² area during 40 minutes of time span, the energy flux of light just before it falls on the surface is ___________ W/cm². (Round off to the Nearest Integer)

(Assume complete absorption and normal incidence conditions are there)