Physics
The figure given below shows the cooling curve of pure wax material after heating. It cools from A and B and solidifies along BD. If L and c represents the value of latent heat and the specific heat of liquid wax, then the ratio of is
- 20
- 40
- 60
- 100
Calorimetry
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Answer
20
Reason — Curve AB represents the cooling of wax material, the specific heat of the cooling of wax material is given by C, and temperature change Δt = 90°C − 80°C
Heat supplied in 2 min = m x c x △T
= m x c x (90-80) = 10mc …..[1]
Curve BD represents the latent heat of fusion during the solidification of wax material for the next 4 minutes. It is represented by
Q = mL …..[2]
As process of solidification takes twice as long as the cooling process,
∴ 2[10mc] = mL [From Eq 1 & 2]
20mc = mL
20c = L
Hence, = 20
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