Advertisements
Advertisements
प्रश्न
The mechanical equivalent of heat ____________ .
विकल्प
has the same dimension as heat
has the same dimension as work
has the same dimension as energy
is dimensionless
Advertisements
उत्तर
is dimensionless
If the mechanical work done (W) produces the same temperature change as heat (H),then the mechanical equivalent of heat (J) is equal to W/H. Thus,
J = W/H
Since the unit of work and heat is the same, mechanical equivalent of heat is dimensionless.
APPEARS IN
संबंधित प्रश्न
A metal sphere cools at the rate of 4°C / min. when its temperature is 50°C. Find its rate of cooling at 45°C if the temperature of surroundings is 25°C.
Compute the temperature at which the r.m.s. speed of nitrogen molecules is 832 m/s. [Universal gas constant, R = 8320 J/k mole K, molecular weight of nitrogen = 28.]
The light from the Sun is found to have a maximum intensity near the wavelength of 470 nm. Assuming the surface of the Sun as a black body, the temperature of the Sun is _____________.
[Wien's constant b = 2 .898 x l0- 3mK]
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?
1000 tiny mercury droplets coalesce to form a bigger drop. In this process, temperature of the drop _______ .
(A) increases
(B) may increase or decrease
(C) decreases
(D) does not change
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.
A spherical shell is heated. The volume changes according to the equation Vθ = V0 (1 + γθ). Does the volume refer to the volume enclosed by the shell or the volume of the material making up the shell?
An aluminium sphere is dipped into water at 10°C. If the temperature is increased, the force of buoyancy
Is heat a conserved quantity?
In a calorimeter, the heat given by the hot object is assumed to be equal to the heat taken by the cold object. Does it mean that heat of the two objects taken together remains constant?
As the temperature is increased, the time period of a pendulum
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?
Two objects are said to be in thermal contact if they can exchange heat energy.
The normal temperature of our body is 37°C.
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.
What is the dimensional formula of heat?
The concept of thermal equilibrium, where heat flows between bodies until they reach the same temperature, is the basis of which law of thermodynamics?
