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प्रश्न
1.0 kg of water is contained in a 1.25 kW kettle. Calculate the time taken for the temperature of water to rise from 25° C to its boiling point of 100°C. Specific heat capacity of water = 4.2 J g-1K-1.
उत्तर
m = 1.0 kg; Δt = 100 - 25 = 75° C
Specific heat capacity = 4.2 J g-1 k-1 = 4200 J kg-1 k-1
Power of kettle = 1.25 kw = 1250 watt
Let time be t second,
ε = P × t and θ = m c Δt
∴ P × t = m c Δt
∴ 1250 × t = 1 × 4200 × 75
∴ t = `(4200 xx 75)/1250`
∴ t = 252 sec
∴ t = 4 min 12 sec
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संबंधित प्रश्न
(i) Define Calorimetry.
(ii) Name the material used for making a Calorimeter.
(iii) Why is a Calorimeter made up of thin sheets of the above material answered in (ii).
Write the SI unit of:
(i) Amount of heat
(ii) Heat capacity
(iii) Specific Heat capacity
State the principle of calorimeter and define calorie and kilocalorie.
Give scientific reasons for the following:
Bottled drinks are cooled more effectively when surrounded by lumps of ice than by cold water at 0°.
Ice cream appears colder to the mouth than water at 0°C. Give a reason.
Which has more heat: 1 g of ice at 0°C or 1 g of water at 0°C? Give reason.
Calculate the heat energy that will be released when 5.0 kg of steam at 100°C condenses to form water at 100°C. Express your answer in S.I. unit. (Specific latent heat of vaporization of steam is 2268 kj/kg.)
A copper calorimeter of mass 50g contains 100g of water at 20°C. A metallic piece of mass 250 g is heated to 100°C and is then dropped into the calorimeter. The contents of the calorimeter are well stirred and its final highest temperature is recorded to be 28 °C. If the specific heat capacity of water is 4.2 J/g°C and of copper is 0.4 J/g°C, find:
(i) the heat gained by water,
(ii) the heat gained by calorimeter,
(iii) total heat supplied by the metal piece, and
(iv) the specific heat capacity of metal.
With the help of a neat diagram, explain the working of a calorimeter.
