D) The eyes in the tree are reflecting light from the torch into the man's eyes.
Answer:
The density of block is 2 g/mL.
Explanation:
Density:
Density is equal to the mass of substance divided by its volume.
Units:
SI unit of density is Kg/m3.
Other units are given below,
g/cm3, g/mL , kg/L
Formula:
D=m/v
D= density
m=mass
V=volume
Symbol:
The symbol used for density is called rho. It is represented by ρ. However letter D can also be used to represent the density.
Given data:
mass of block = 12 g
volume = 6 mL
density = ?
Now we will put the values in the formula,
d= m/v
d = 12 g/ 6 mL
d = 2 g/mL
so, the density of block is 2 g/mL .
Answer:
Argon has 8 valence electrons making it non reactive.
Explanation:
Reactive chemicals are store in containers filled with Argon gas because the argon gas is non reactive. This is true because the argon gas has completely filled octet structure.
This can further be explained by writing the electronic configuration of argon.
The electronic configuration of argon is given below:
Ar (18) => 1s² 2s²2p⁶ 3s²3p⁶
Valence electron => 3s²3p⁶ = 2 + 6 = 8
From the above illustration, we can see that the outermost shell (i.e 3s²3p⁶) is having 8 electrons indicating that it is completely filled as the maximum number of electrons any shell can accommodate outside the first shell is 8 electrons. Thus, argon has 8 valence electrons ( i.e electrons in the outermost shell) and hence it is non reactive as the outermost shell is completely filled.
Answer:
The acceleration of an object as produced by a net force is directly proportional to the magnitude of the net force, in the same direction as the net force, and inversely proportional to the mass of the object
Explanation:
12 times breathe give 240 ml of pure 
. Each breathe gives 20 ml of .
Let us consider, volume of air per breathe= x ml.
Pure from inhaled air= 
ml and Pure from exhaled air= 
ml.
Pure from inhaled and exhaled air= 20 ml
So, + = 20
Therefore, x = 55.5 ml
So, volume of air per breath= 55.5 ml.
