Advertisements
Advertisements
प्रश्न
A body cools from 80° C to 70° C in 5 minutes and to 62° C in the next 5 minutes. Calculate the temperature of the surroundings.
Advertisements
उत्तर
Average Temperature,
T1 = 80 +70/2 = 75°C
Average Temperature,
T2 = 70 + 62/2 = 66°C
We know, that `"dT"/"dt"` = − k (T − T0)
Where, T is a average temperature
T0 is surrounding temperature
`10/5` = − k (75 − T0) ..............(1)
`8/5` = − k (66 − T0) ............(2)
Dividing (1) and (2)
`10/8=(75-"T"_0)/(66-"T"_0)`
T0 = 30°C
APPEARS IN
संबंधित प्रश्न
The susceptibility of magnesium at 300 K is 2.4 x 10-5. At what temperature will the susceptibility increase to 3.6 x 10-5?
What is the temperature of the triple-point of water on an absolute scale whose unit interval size is equal to that of the Fahrenheit scale?
A body cools from 62°C to 54°C in 10 minutes and to 48°C in the next 10 minutes. Find the temperature of the surroundings.
Can the bulb of a thermometer be made of an adiabatic wall?
Which of the curves in the following figure represents the relation between Celsius and Fahrenheit temperatures?
The temperature of water at the surface of a deep lake is 2°C. The temperature expected at the bottom is
Is heat a conserved quantity?
Should a thermometer bulb have large heat capacity or small heat capacity?
Which of the following pairs of physical quantities may be represented in the same unit?
The mechanical equivalent of heat ____________ .
The heat capacity of a body depends on
(a) the heat given
(b) the temperature raised
(c) the mass of the body
(d) the material of the body
The temperature of an object is observed to rise in a period. In this period
(a) heat is certainly supplied to it
(b) heat is certainly not supplied to it
(c) heat may have been supplied to it
(d) work may have been done on it
Heat and work are equivalent. This means, ____________ .
A pendulum clock shows correct time at 20°C at a place where g = 9.800 m s–2. The pendulum consists of a light steel rod connected to a heavy ball. It is taken to a different place where g = 9.788 m s–1. At what temperature will the clock show correct time? Coefficient of linear expansion of steel = 12 × 10–6 °C–1.
The volume of a glass vessel is 1000 cc at 20°C. What volume of mercury should be poured into it at this temperature so that the volume of the remaining space does not change with temperature? Coefficients of cubical expansion of mercury and glass are 1.8 × 10–6 °C–1 and 9.0 × 10–6 °C–1 , respectively.
The densities of wood and benzene at 0°C are 880 kg m3 and 900 kg m–3 , respectively. The coefficients of volume expansion are 1.2 × 10–3 °C–1 for wood and 1.5 × 10–3 °C–1for benzene. At what temperature will a piece of wood just sink in benzene?
A steel ball that is initially at a pressure of 1.0 × 105 Pa is heated from 20°C to 120°C, keeping its volume constant.
Find the pressure inside the ball. Coefficient of linear expansion of steel = 12 × 10–6 °C–1and bulk modulus of steel = 1.6 × 1011 Nm–2.
Define one mole.
One day in 1922, the air temperature was measured at 59°C in the shade in Libya ______.
Heat is measured in Celsius or centigrade.
The degree of hotness and coldness of a body is called ______.
Two identical beakers A and B contain equal volumes of two different liquids at 60°C each and is left to cool down. Liquid in A has a density of 8 × 102 kg/m3 and specific heat of 2000 J kg-1 K-1 while the liquid in B has a density of 103 kg m-3 and specific heat of 4000 J kg-1 K-1. Which of the following best describes their temperature versus time graph schematically? (assume the emissivity of both the beakers to be the same.)
An earthen pitcher loses 1 gm of water per minute due to evaporation. If the water equivalent of the pitcher is 0.5 kg and the pitcher contains 9.5 kg of water, calculate the time required for the water in a pitcher to cool to 28°C from the original temperature of 30°C. Neglect radiation effects. The latent heat of vaporization in this range of temperature is 580 Cal/gm and the specific heat of water is 1 Cal/gm°C.
Heat given to a body that raises its temperature by 1°C is ______.
The temperature of a liquid drops from 365 K to 361 K in 2 min. Find the time during which the temperature of the liquid drops from 344 K to 342 K.
(Take, room temperature = 293 K)
The average kinetic energy of molecules of a gas is directly related to which physical quantity?
