Advertisements
Advertisements
Question
A person's skin is more severely burnt when put in contact with 1 g of steam at 100°C than when put in contact with 1 g of water at 100°C. Explain
Solution
Steam has greater energy than boiling water due to latent heat of vapourisation. The internal energy of the vapour at 100 oC is greater than the internal energy of the boiling water at the same temperature. Thus, steam burns the skin more severely than boiling water.
APPEARS IN
RELATED QUESTIONS
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.]
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.
The susceptibility of magnesium at 300K is 1.2 x 10-5. At what temperature will the susceptibility increase to 1.8 X 10-5?
The substance which allows heat radiations to pass through is _______.
(A) iron
(B) water vapour
(C) wood
(D) dry air
The density of water at 4°C is supposed to be 1000 kg m–3. Is it same at sea level and at high altitude?
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?
A spinning wheel A is brought in contact with another wheel B, initially at rest. Because of the friction at contact, the second wheel also starts spinning. Which of the following energies of the wheel B increases?
(a) Kinetic
(b) Total
(c) Mechanical
(d) Internal
Water equivalent of a body is measured in ___________ .
Two bodies at different temperatures are mixed in a calorimeter. Which of the following quantities remains conserved?
The mechanical equivalent of heat ____________ .
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
A circular hole of diameter 2.00 cm is made in an aluminium plate at 0°C. What will be the diameter at 100°C? α for aluminium = 2.3 × 10–5 °C–1.
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 rod of length 1 m rests on a smooth horizontal base. If it is heated from 0°C to 100°C, what is the longitudinal strain developed?
In hot summer after a bath, the body’s __________.
Two objects are said to be in thermal contact if they can exchange heat energy.
One day in 1922, the air temperature was measured at 59°C in the shade in Libya ______.
Heat is measured in Celsius or centigrade.
