Answer:
the stronger light 5.5 m apart from the total illumination
Explanation:
From the problem's statement , the following equation can be deducted:
I= k/r²
where I = intensity of illumination , r= distance between the point and the light source , k = constant of proportionality
denoting 1 as the stronger light and 2 as the weaker light
I₁= k/r₁²
I₂= k/r₂²
dividing both equations
I₂/I₁ = r₁²/r₂²=(r₁/r₂)²
solving for r₁
r₁ = r₂ * √(I₂/I₁)
since we are on the line between the two light sources , the distance from the light source to the weaker light is he distance from the light source to the stronger light + distance between the lights . Thus
r₂ = r₁ + d
then
r₁ = (r₁ + d)* √(I₂/I₁)
r₁ = r₁*√(I₂/I₁) + d*√(I₂/I₁)
r₁*(1-√(I₂/I₁)) = d*√(I₂/I₁)
r₁ = d*√(I₂/I₁)/(1-√(I₂/I₁)) =
r₁ = d/[√(I₁/I₂)-1)]
since the stronger light is 9 times more intense than the weaker
I₁= 9*I₂ → I₁/I₂ = 9 →√(I₁/I₂)= 3
then since d=11 m
r₁ = d/[√(I₁/I₂)-1)] = 11 m / (3-1) = 5.5 m
r₁ = 5.5 m
therefore the stronger light 5.5 m apart from the total illumination
Answer: The given reaction redox reaction not a combustion reaction.
Explanation:
Redox Reaction is defined chemical reaction in which oxidation and reduction takes place simultaneously. In Oxidation addition of oxygen occurs and in reduction addition of hydrogen occurs.

Potassium is getting oxidized by addition of oxygen.
Water us reduced to hydrogen gas by removal of oxygen
Combustion reaction is defined as chemical reaction in which burning of a chemical compound or element takes place in presence of oxygen occurs.
In the given reaction, oxygen molecule is absent which means this reaction is not combustion reaction.
Hence ,the given reaction redox reaction not a combustion reaction.
Depositional landforms are the visible evidence of processes that have deposited sediments or rocks after they were transported by flowing ice or water, wind or gravity. Examples include beaches, deltas, glacial moraines, sand dunes and salt domes
The branch of science that deals with the identification of the substances of which matter is composed
you can learn by reading about it or google it