Advertisements
Advertisements
प्रश्न
Heat energy is supplied at a constant rate to 100g of ice at 0 °C. The ice is converted into water at 0° C in 2 minutes. How much time will be required to raise the temperature of water from 0 °C to 20 °C? [Given: sp. heat capacity of water = 4.2 J g-1 °C-1, sp. latent heat of ice = 336 J g-1].
100 g of ice at 0°C receives a steady flow of heat energy. At 0°C, the ice melts into the water in 2 minutes. How long will it take to bring the temperature of the water up to 20 degrees? (Specific latent heat of ice = 336 J/g, Specific heat capacity of water = 4.2 J/g °C).
Advertisements
उत्तर
Heat energy required to melt 100 g of ice at 0 °C is
Q = mL = 100 × 336=33600 J
Therefore, heat energy supplied per minute is
`33600/2=16800 "J min"^-1`
Now, heat energy required to raise the temperature of water from 0°C to 20°C is
Q'=mc × rise in temperature =100 × 4.2 × 20 = 8400 J
If time required for this heat gain is t minutes, then Heat energy supplied in t minutes is
`16800 xx "t"=8400`
`therefore "t" =8400/16800`
`"t" = 0.5 "min"`
`"t" = 30 "s"`
संबंधित प्रश्न
Water in lakes and ponds do not freeze at once in cold countries. Give a reason is support of your answer.
Heat supplied to a solid change it into liquid. What is this change in the phase called?
An equal quantity of heat is supplied to two substances A and B. The substance A shows a greater rise in temperature. What can you say about the heat capacity of A as compared to that of B?
Give two reasons as to why copper is preferred over other metals for making calorimeters.
If, in a central heating system, steam enters a radiation pipe at 100°C and water leaves the radiation pipe at 100°C, can this radiation pipe heat a room? Give an explanation for your answer.
Ice-cream at 0°C feels colder than water at 0°C. Give reason for this observation.
1 kg of water freezes to form ice at 0°C. What amount of heat is withdrawn?
Consider the statement given below and choose the correct option.
Assertion: Radiation is a form of heat transfer which takes place only in vacuum.
Reason: The thermal energy is transferred from one part of a substance to another part without the actual movement of the atoms or molecules.
Calculate the amount of heat energy required to raise the temperature of 200 g of copper from 20°C to 70°C. Specific heat capacity of copper = 390 J kg-1 K-1.
