Answer:
The upper and lower limits for the room-temperature thermal conductivity of a magnesium oxide material having a volume fraction of 0.10 of pores that are filled with still air are
Ku = 38.252 W/mK
K lower = 0.199 W/mK
Explanation:
As we know
Ku = Vp * Kair + Vmagnesium * K metal
Ku = 0.10 *0.02 + (1-0.25) * 51
Ku = 38.252 W/mK
The lower limit
K lower = Kmetal* Kair/( Vp * Kmetal + Vmetal * K air)
K lower = (0.02*51)/(0.10*51 + 0.90 * 0.02)
K lower = 0.199 W/mK
Answer:
Explanation:
For transitions:
So, 
and 
(As the hydrogen has to ionize)
Thus,
Answer : The correct option is, (2) Energy is absorbed as bonds are broken.
Explanation :
As we know that the bonds are formed and breaks during the chemical reaction. Some energy is released or absorbed when the bonds are formed and breaks during the chemical reaction.
During the bond breaking, some energy is required to break the bonds.
During the bond formation, some energy is released to the formation of the bonds.
In the given reaction, the bond between the hydrogen-hydrogen in 
are breaking into two hydrogen. That means during the bond breaking, some energy is required or absorbed to break the bonds.
Hence, the correct option is, (2) Energy is absorbed as bonds are broken.
Answer:
x=34
y=20
Explanation:
let the first number be 'x'
let the second number be 'y'
Equation 1:-
x + y = 54
Equation 2:-
x = y + 14 (Since one exceeds the other by 14)
Substituting Equation 2 in Equation 1:-
(y + 14) + y = 54
=> y + 14 + y = 54
=> 2y + 14 = 54
=> 2y = 54 - 14
=> 2y = 40
=> y = 40/2
=> y = 20
Now in Equation 1:-
x + y = 54
Substituting y=20,
x + 20 = 54
x = 54 - 20
x = 34
The study of the elements and forms of matter.
