Explanation:
When water is boiled in the flask . Some portion of it is evaporated out . Now when cork is placed on it and is placed in the ice box . It cools down , by which the pressure inside decreases .
Due to decrease of pressure , the boiling point of water also decreases . Now it can boil at lower temperature . Thus it starts boiling at lower temperature even , when placed in the ice box .
Answer:
784 J
Explanation:
Work is force times distance.
W = Fd
W = mgd
W = (40 kg) (9.8 m/s²) (2 m)
W = 784 J
Answer:
The correct option is;
B) The specific heat of ice is less than that of water.
Explanation:
Here we have
Let the amount of energy added to the ice at -10 C to raise the temperature to -5 C be X J
Let the amount of energy added to the water at 15 C to raise the temperature to 20 C be Y J
We know that the heat required, ΔQ to raise the temperature of a substance is given by
ΔQ = m·c·Δθ
Where:
m = Mass of the substance
c = Specific heat capacity
Δθ = Temperature change
Since the mass of the ice and the water are the same, so also is the change in temperature, (-5 - (-10) = 5 and 20 - 15 = 5) we have
for m₂·c₂·Δθ₂ > m₁·c₁·Δθ₁
Where:
m₁, c₁, Δθ₁, is for the ice and m₂, c₂, Δθ₂ is for the water and
m₁ = m₂
Δθ₁ = Δθ₂
Therefore,
c₂ > c₁ = c₁ < c₂
That is the specific heat capacity of the ice is lesser than the specific heat capacity of the water.
Work = N × m = 50 x 40 = 2000 J
