Physics Test - ...

A child running at a temperature of 101oF is given an antipyrin (i.e., medicine that lowers fever) which causes an increase in the rate of evaporation of sweat from his body. If the fever is brought down to 98oF in 20 min, what is the average rate of extra evaporation caused by which heat is lost. The mass of child is 30 kg. The specific heat of the human body is approximately the same as that of water and latent heat of evaporation of water at that temperature is about 580 cal/g.

A sphere of radius 10 cm is hung inside an oven whose walls are at a temperature of 1000 K. Calculate the total heat energy incident per second on the sphere. Given that Stefan's constant, σ = 5.67 × 10⁻⁸ W m⁻¹ °C⁻⁴.

The thermal conductivity of a rod is 2. What is its thermal resistivity?

The black body spectrum of an object Q₁ is such that its radiant intensity (i.e., intensity per unit wavelength interval) is maximum at a wavelength of 100 nm. Another object O₂ has the maximum radiant intensity at 600 nm. The ratio of power emitted per unit area by source O₁ to that of source O₂ is

Assertion: In a process if initial volume is equal to the final volume, work done by the gas is zero.

Reason: In an isochoric process work done by the gas is zero.

The ratio of thermal capacities of two spheres A and B, if their diameters are in the ratio 1:2, densities in the ratio 2:1, and the specific heat in the ratio of 1:3, will be

The rate of emission of radiation of a black body at temperature 27℃ is E₁. If its temperature is increased to 327℃, the rate of emission of radiation is E₂. The relation between E₁ and E₂ is

Two absolute scales A and B have triple points of water defined to be 200 A and 350 B. What is the ratio of TA and TB ?

Following graph shows the correct variation in intensity of heat radiations by black body and frequency at a fixed temperature

The thermodynamic state of two moles of an ideal gas is changed from A to B along the path shown. The net work done by the gas is