Heat flows naturally from a warmer object (higher energy) to a cooler one (lower energy).
Answer:
<u>Chemical changes</u> are recognized when a substance changes its properties permanently and it cannot be the same substance as before.
Instead the<u> physical changes</u><u> </u>implies that if you can return to the same substance through a reverse process.
Explanation:
A chemical change is, by example, a combustion, if a sheet of paper burns, its result is ashes, the ashes cannot go back to being a sheet of paper because its properties changed, heat energy was generated that changed matter permanently.
A physical change, by example, is that of freezing water, the water becomes ice, but this can easily become water again if the temperature is increased, its properties do not change and the chemistry of the substance does not change.
Answer:
a) 9.72 mm
b) 4.86 mm
Explanation:
wave length of light λ is 580 nm = 580 \times 10⁻⁹ m
Width of slit d = 0.215\times 10⁻³ m
Distance of screen D = 1.8 m.
Width of one fringe = 
Putting the values we get fringe width
= 
=4.86 mm.
a) Width of central maxima = 2 times width of one fringe
= 2 times 4.86
=9.72 mm
b) width of each fringe except central fringe is same , no matter what the order is.Only brightness changes .
So width of either of the two first order bright fringe will be same and it will be
= 4.86 mm.
Answer : The static friction depends on two factors
1. Roughness of the surface
2. Force
Explanation : Friction occur when surface is not smooth.
The formula of friction is

Static friction depends on the roughness of the surface and force which is trying to push to object along the surface.
Static friction is caused by the attraction between two surfaces that are in contact. when the surface will rough and the object will heavier then the force will be larger.