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ICSE Class 10 Physics Question 2 of 27

Solved Sample Paper 1 — Question 2

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Question 1(ii)

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 Lc\dfrac{\text{L}}{\text{c}} is

  1. 20
  2. 40
  3. 60
  4. 100
The figure 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 L/C is? Physics Sample Paper Solved ICSE Class 10.
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, Lc\dfrac{\text{L}}{\text{c}} = 20