Answer:
B. nuclear fusion
Explanation:
Atomic fusion is a process in which two or more lighter nuclei combine to form a heavier nucleus.
The mass of the single nucleus thus formed is lighter than the initial mass.
There is a difference in mass in the heavier nucleus thus formed. According to Einstein's mass-energy equation, the change in mass is equated towards energy.
The energy liberated in the process is called as thermo-nuclear energy.
As in the case of isotopes of hydrogen fuses to form helium, the nuclear reaction is given by relation
₁H³ + ₁H² → ₂He⁴ + ₀n¹ + energy
Thus, the nuclear reaction of hydrogen isotopes forming helium is nuclear fusion.
B. Yard
the other answers C. & D. are metric A is a unit of temperature
Answer:
There are many types of magnets, which are generally divided into two categories: permanent magnet and a soft magnet.
Explanation:
The true statements are B and C.
This comes from the following facts:
Even when heat is added to a substance in a change of phase the temperature does not increases since this heat is latent heat.
Answer:
T'=70.92°C
Explanation:
Given that
V= 100 L=0.1 m³
P=400 KPa
T=25°C
Work done on the air = 15 KJ
W= -15 KJ
If we assume that air is ideal gas
P V = m R T
R=0.287 KJ/kg.K for air
T= 273 + 25 = 298 K
By putting the values
P V = m R T
400 x 0.1 = m x 0.287 x 298
m=0.46 kg
From first law of thermodynamics
Q= ΔU +W
Insulated piston–cylinder , Q=0
ΔU = m Cv ΔT
ΔU = - W
Cv = 0.71 KJ/kg.k for air
0.46 x 0.71 x (T' -25) = 15
T'=70.92 °C
So the final temperature of air is T'=70.92 °C
