**Heat & Temperature**

- This video introduces the concept of thermodynamics and the underlying concept at molecular level of an object.
- This video explains the fundamental concept of thermodynamics i.e heat and temperature in terms of perception of touch and internal energy respectively.
- This video explains the method of measuring the temperature of a body and the underlying law called zeroth law of thermodynamics.
- This video explains the different temperature scales used to measure the temperature of a body like degree Celsius or centigrade, degree Fahrenheit and Kelvin. It also states the relationship between these scales.
- At what temperature do the Celsius and Fahrenheit readings have the same numerical value?
- This video explains the phenomena of expansion or contraction of a body on heating or cooling respectively in terms of intermolecular energy consideration. It also explains the law governing the expansion of a body and linear coefficient of expansion.
- A steel wire of given cross-sectional area is held straight (but under no tension) by attaching it firmly to two points a distance apart at a temperature of 400C. If the temperature now decreases to -400C, and if the two tie points remain fixed, what will be the tension in the wire? Given the Young’s modulus and coefficient of linear expansion for steel.
- Two rods of different materials having coefficients of thermal expansion α1 and α2 and Young's modulus Y1 and Y2 are fixed between two rigid and massive walls. The rods are heated to the same temperature. If there is no bending of the rods, find the ratio of young’s modulus so that the thermal stresses developed in them are equal.
- It is desired to put an iron rim on a wooden wheel. The diameter of the wheel is 1 meter and the inside diameter of the rim is 0.98 meter. If the rim is at a temperature of 20 0C initially, to what temperature must it be heated to just fit onto the wheel?
- This video explains the phenomenon of linear expansion in bimetallic strip having different coefficient of linear expansion.
- A bimetallic strip is formed out of two identical strips of two different metals. The co-efficient of linear expansion of the two metals are α1 and α2. When the temperature of the strip is increased by ΔT, it bends to form an arc of radius of curvature R. Then which of the following is correct for R. a) Proportional to ΔT b) inversely proportional to ΔT c) Proportional to (α1 - α2) d) inversely proportional to (α1 - α2)
- These video explains the superficial and volume expansion in 2-D and 3-D respectively. It also explains the relationship between coefficients of linear, superficial and volume expansion.
- A sheet of copper has a given area at temperature of -50 0C. Find the area of this sheet at temperature of 100 0C.
- What is the increase in Surface area of a ball, when its temperature is increased by ΔT. Given, the coefficient of linear expansion of material is α.
- This video explains the anomalous expansion of water at different temperature along with relative changes in intermolecular structure of water at different stages.
- At which of the following temperature, density of water is maximum? (a) 00C (b) 20C (c) 40C (d) 60C
- This video explains the intrinsic property of any object called heat capacity which is defined as the amount of heat required to bring a unit change in the temperature in Kelvin scale, without changing the phase of the object. It also explains the unit of heat i.e joules and calories and their relation.
- In an experiment is it observed that it takes 3360 J of heat to change the temperature of 2 kg glass by 2 0C and it takes 4 kilocalorie of heat to change the temperature of 1 kg Water by 4 0C. Compare the specific heat capacities of glass and water.
- It explains the latent heat of body which is measure of amount of heat required per unit mass to change in phase of the body without changing its temperature. It also explains the latent heat of fusion and latent heat of vaporization.
- 1 kg mass of Ice at a temperature of -100 0C is converted into Steam at 100 0C. Calculate the heat required in each of the following steps. (a) ice at -100 0C is brought to ice at 0 0C (b) ice at 0 0C is converted into water at 0 0C (c) water at 0 0C is brought to water at 100 0C (d) water at 100 0C is converted into steam at 100 0C Given: Specific heat capacity of ice, Specific heat capacity of water, Latent heat of Fusion of ice, Latent heat of Vaporization of water
- A block of ice at a temperature of -10 0C is slowly heated and converted to steam at 100 0C. Which of the following curves represents the phenomenon qualitatively?
- This video illustrates the construction and working of a calorimeter used to measure the specific heat capacities and latent heat of substances, based on the principle of calorimetry which governs the heat exchange between bodies in a closed and isolated environment.
- 2 kg mass of ice at temperature -20 0C is mixed with 5 kg of water at 20 0C in an insulating vessel having a negligible heat capacity. Calculate the final mass of water in the vessel. Given the specific heat of water and ice, the latent heat of fusion of ice.
- 300 g mass of water at temperature of 25 0C is added to 100 g of ice at 0 0C. The final temperature of the mixture is….?
- Steam at temperature of 100 0C is passed into 1.1 kg mass of water contained in a calorimeter of water equivalent 0.02 kg at 15 0C till the temperature of the calorimeter rises to 80 0C. The mass of steam condensed in kilogram is….?
- 400g of ice at temperature of 253 Kelvin is mixed with 0.05 kg of steam at 100 0C. Given the latent heat of vaporization of steam, Latent heat of fusion of ice, Specific heat of ice; find the resultant temperature of the mixture.
- What should be the lengths of steel and copper rod so that the length of steel rod is 5 cm longer than the copper rod at all temperatures?
- Two rods, one made of aluminium and the other made of steel, have initial lengths l1 and l2 respectively. The coefficients of linear expansion for aluminium and steel are α1 and α2 respectively. If the length of each rod increases by the same amount when their temperature is raised by T 0C, then the ratio l1 /(l1 + l2) will be equal to..?
- A composite rod is made by joining a copper rod, end to end, with a second rod of a different material but of the same cross section. At a given temperature, the composite rod is 1m in length of which the length of the copper rod is 30 cm. When temperature is increased, the length of the composite rod increases by 2 mm. The co-efficient of linear expansion of copper is given. Find the coefficient of linear expansion of the second rod.
- A steel scale measures the length of a copper rod when both are at same temperature. What will be the scale reading for the length of the rod when temperature of both is increased to an equal scale. Coefficient of linear expansion for copper and steel is known.
- A traditional clock has a pendulum made of metal. The clock is adjusted to have a period of 1s exactly at temperature of 15 0C. When operated at 40 0C, will it be fast or slow? How much will the clock be in error 1 month after it is set?
- At a given temperature, a pendulum clock shows accurate time at a place where acceleration due to gravity is known. This pendulum is taken to a place where acceleration due to gravity is different? Find the temperature at which it will give accurate time again.
- If an anisotropic solid has coefficients of linear expansion ax, ay, and az for three mutually perpendicular directions in the solid, what is the coefficient of volume expansion for the solid?
- A substance of mass M requires power input P to remain in the molten state at its melting point. When the power source is turned off, the sample completely solidifies in time t. The latent heat of fusion of the substance is…?
- A 1 kW electric kettle contains 2 liter water at a temperature of 27 0C. The kettle is operated for 10 minutes. If heat is lost to the surrounding at a constant rate of 160 J/sec, the temperature attained by water in 10 minutes will be….?
- In an industrial process 10 kg mass of water per hour is to be heated from a temperature of 20 0C to 80 0C. To do this, steam at 150 0C is passed from a boiler into a copper coil immersed in water. The steam condenses in the coil and is returned to the boiler as water at 90 0C. How many kg of steam is required per hour? Given the specific heat of steam and latent heat of steam.
- 20 g mass of ice in 10 g copper calorimeter is originally at temperature -30 0C. How much steam at 100 0C must be condensed in the calorimeter if the ice is to be changed to water and heated to 40 0C? Given the latent heat of vaporization of water, latent heat of fusion ice, specific heat of copper and specific heat of ice.
- The temperatures of equal masses of three different liquid A, B and C are 12 0C, 19 0C and 28 0C respectively. The temperature when A and B are mixed is 16 0C and when B and C are mixed, it is 23 0C. What should be the temperature when A and C are mixed?
- Ice at 0 0C is added to 200 g of water initially at 70 0C in a vacuum flask. When 50 g of ice has been added and has all melted, the temperature of the flask and contents is 40 0C. When a further 80 g of ice has been added and has all melted, the temperature of the whole becomes 10 0C. Neglecting heat loss to surroundings calculates latent heat of fusion of ice.
- An open iron container of volume 500 mL is full of glycerin at 10 0C. What volume of glycerin overflows when the container if heated to 160 0C?
- A one liter flask contains some mercury. It is found that at different temperatures the volume of air inside the flask remains the same. What is the volume of mercury in flask? Given the coefficient of linear expansion of glass and coefficient of volume expansion of mercury.
- Let Δl1 be the length of the column in a mercury thermometer which corresponds to a rise in temperature ΔT if the expansion of the glass is neglected. Let Δl2 be the actual length which allows for the expansion of the glass. Calculate the numerical value of (Δl1 - Δl2) / Δl1. Only the bulb is immersed in the object whose temperature is being measured.
- The mercury in a thermometer has volume of 210 mm3 at 0 0C, at which temperature the diameter of the bore is 0.2 mm. How far apart are the degree marks on the stem?
- A vessel is completely filled with 500 gram of water and 1000 gram of mercury. When 21200 calories of heat are given to it, 3.52 gram of water overflows. Calculate the coefficient of volume expansion of mercury. Expansion of vessel may be neglected. Given, coefficient of volume expansion of water, density & specific heat of mercury.
- When the expansion of a liquid in a vessel is measured to obtain the coefficient γ, what is actually obtained is γ relative to the material of which the container is made. Figure shows an apparatus from which the correct value of γ can be found without any knowledge of γ for the container. Show that: γ = (1/T) [(Ht-Ho)/Ho]
- A sinker of weights W0 has an apparent weight W1 when weighed in a liquid at a temperature T1 and W2 when weighed in the same liquid at a temperature T2. The coefficient of cubical expansion of the material of sinker is given. What is the coefficient of volume expansion of the liquid?
- A metal ball immersed in alcohol weighs W1 at 0 0C and W2 at T 0C. The coefficient of cubical expansion of metal is less than that of alcohol. If the density of the metal is large compared to that of alcohol, then which of the following is correct? (a)W1>W2 (b) W1 = W2 (c) W1 < W2 (d) W2 = W1/2
- A metal piece weighs 100 gm in air. It weighs 68 gm when immersed in a liquid at 10 0C and 69 gm in the same liquid at 22 0C. Find the coefficient of linear expansion of the metal. Given the density of liquid at 10 0C and 22 0C.
- A solid floats on a liquid. The coefficients of volume expansion of the solid and liquid are given. If their temperature is increased by ΔT, the fraction of the volume of solid submerged in liquid change by a factor of…?
- At 0 0C, the densities of wood and benzene are given. The coefficient of volume expansion of wood and that of benzene is known. Find the temperature at which a piece of wood will just sink in benzene.
- A metal cube of coefficient of linear expansion α is floating in a liquid of coefficient of volume expansion γ. When the temperature is raised by ΔT, the depth up to which the cube is submerged in the liquid remains unchanged. If the expansion of container is ignored, the relation between coefficients of linear and volume expansion is….?
- A flask is completely filled with mercury and is sealed off at 10 0C. Find the pressure within the flask at 160 0C. Ignore the expansion of the glass. Given the bulk modulus for mercury, B and Co-efficient of volume expansion.
- A uniform solid sphere of radius Ro and mass M is set spinning with angular speed ωo about a diameter. If its temperature is now increased without disturbing the sphere, what will be its new angular speed and rotational kinetic energy?
- An ice cube of mass 0.1 kg is placed in an isolated container which is at 227 0C. The specific heat capacity Cc of the container varies with temperature T according to the relation Cc = A + BT, where A and B are constants. If the final temperature of the container is 27 0C, find the mass of the container. ( Given the latent heat of fusion and specific heat of water)