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प्रश्न
A molten metal of mass 150 g is kept at its melting point 800℃. When it is allowed to freeze at the same temperature, it gives out 75,000 J of heat energy.
- What is the specific latent heat of the metal?
- If the specific heat capacity of metal is 200 J kg-1 K-1, how much additional heat energy will the metal give out in cooling to -50℃?
उत्तर
- Mass of metal = 150 g
Specific latent heat of metal
L = `"Q"/"m"`
= `75000 / 150`
= 500 J g-1 - Specific heat capacity of metal is 200 J kg-1K-1.
Change in temperature= 800 − (−50)
= 850°C (or 850 K).
ΔQ = mcΔT
= 0.15 × 200 × 850
= 25500 J
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