Transfer of heat - class-XI
Description: transfer of heat | |
Number of Questions: 95 | |
Created by: Mira Shah | |
Tags: transfer of heat thermal energy transfers paths of heat flow physics thermal physics temperature and heat heat heat and thermodynamics heat and temperature heat energy transfers thermal properties of matter |
A geyser heats water flowing at the rate of 4 litre per minutes from 30 C to 85 C. If the geyser operates on gas burner then the amount of heat used per minute is :
A 2 m long wire of resistance 4 ohm and diameter 0.64 mm is coated with plastic insulation of thickness 0.06 mm, when a current of 5 ampere flows through the wire, find the temperature difference across the insulation in steady state if $k=0.16\times { 10 }^{ -2 }cal/\left( cm{ C }^{ 0 }sec \right) $
M g of ice at ${ 0 }^{ \circ }C$ is mixed with M g of water at ${ 10 }^{ \circ }C.$ The final temperature is
Name a medium which is a good insulator of heat.
A cotton sheet is ironed with hot electricity. How is energy transferred through the metal base of the iron to the sheet?
In the following solids thermal conductivity is maximum for :
Two layers of cloth of equal thickness provide warmer covering than a single layer of cloth of double the thickness, because they :
Thermoflasks and doors of refrigerators have two layered structure with an insulator in between so as:
Mercury is generally used in thermometer because it has a
Which of the following is a good conductor of heat?
What type of conductor should we used to make water pipes in cold countries?
On a cold day when a room temperature is $15^oC$, the metallic cap of a pen becomes much colder than its plastic body, though both are at the same temperature of $15^oC$, because
Two thin walled sphere of different materials ,one with double the radius and one fourth wall thickness of the other are filled with ice If the time taken for complete melting of ice in the sphere of larger radius is $25$ minutes and that for smaller one is $16$ minutes,the ratio of thermal conductivities of the materials of larger sphere to the smaller sphere is
Iron, lead and brass spheres of equal masses are heated to a common temperature and are kept on a sheet of wax. The sphere that passes through the plate first is (lead 0.03 $\operatorname { cal } / \mathrm { g } / ^ { \circ } \mathrm { C }$, iron 0.11 $\operatorname { cal } / \mathrm { g } / ^ { \circ } \mathrm { C }$, brass 0.08 $\operatorname { cal } / \mathrm { g } / ^ { \circ } \mathrm { C }$)
Glaciers melt:
Two rods having thermal conductivities in the ratio of 5:3 and having equal length length and equal cross-section are joined by face to face. If the temperature of free end of first rod is $100^oC$ and temperature of free end of second rod is $20^oc$, then temperature of the junction, is-
Select and write the most appropriate answer from the given aternative in question:
Which of the following substances is ductile?
Two walls of thickness $d _1$ and $d _2$, thermal conductivities $K _1$ and $K _2$ are in contact. In the steady state if the temperatures at the outer surfaces are $T _1$ and $T _2$, the temperature at the common wall will be
$\triangle { H }^{ \circ }$ for reaction:
${ F } _{ 2 }+2HCI\rightarrow 2HF+{ CI } _{ 2 }$
is equal to -352.8kJ. If $\triangle { H } _{ f }^{ \circ }$ for HF is -268.3 kJ ${ mol }^{ -1 }$ then ${ \triangle H } _{ f }^{ \circ }$ of HCI would be:-
A hetaed smooth metallic body is allowed to cool in air. Which of the following statements about its heat loss is incorrect?
Spheres $P$ and $Q$ are uniformly constructed from the same material which is a good conductor of heat and the radius of $Q$is thrice the radius of $P$. The rate of fall of temperature of $P$ is $x$ times that of $Q$ when both are at the same surface temperature. The value of $x$ is:
If we convert a sphere of radius $'r'$ into a cylinder of radius $r$ at same temperature the rate of heat loss will becomes if both are placed at same surrounding-
A sphere, a cube and a thin circular plate, all of same material and same mass, are initially heated to same high temperature. Choose the correct statement.
A metal cylinder of mass 0.5 kg is heated electrically by a 12 W heater in a room and cylinder temperature rises uniformly to $ 25^oC in 5 min $ excess temperature surroundings,
Heat current is maximum in which of the following (rods are of identical dimension)
Assertion (A): When hot water is poured in athick glass tumbler then the tumbler breaks.
Reason (R): Glass is a bad conductor of heat
Metals are good conductors of heat because
In the Ingen Hausz's experiment, the wax melts up to lengths $10cm$ and $25cm$ on two identical rods of different materials. The ratio of thermal conductivities of the two materials is
Two blocks of steel A and B, A being two times heavier than B, are at 40$^o$C. The ratio of heat content of A to B is:
Electric heaters used for cooking have the filament or the heating coil on a plate made up of clay because:
Thermocole lined box is used as a cold storage because.
There are two hollow spheres made of different materials, one with double the radius and one fourth wall thickness of the other are filled with ice. If the time taken for melting the ice completely in larger sphere is $25$ minutes and that for smaller sphere is $16$ minutes, the ratio of the thermal conductivity of the larger sphere to the smaller sphere is :
a corked bottle full of water when frozen will break because.
Read the given statements and select the correct option.
Statement 1: An iron ball at ${35}^{o}C$ is dropped in a mug containing water at $305.15K$. Then the heat will flow from the water to the iron ball.
Statement 2: In convection, heated molecules of a liquid themselves move to carry heat from the hot region to the cold region.
In a room contain air , heat can go from one place to another
Which of the following is a good conductor of heat?
Heat travels much faster in insulators than in conductors.
Which of the following is/are bad conductors of heat?
Name a metal among the following having highest heat conductivity .
When we touch a steel rod and a paper simultaneously, we feel that the rod is colder because:
A good insulator of heat is
Which of the following statement is true?
Which of the following are good conductors of heat?
Which of the following is the very poor conductor of heat ?
Assertion (A): Woolen clothes keep the body warm in winter
Reason (R): Air is bad conductor of heat
Substances which allow heat to pass through them are called:
A coin is dipped in the molten wax in a glass tube. When we heat the upper part of the glass tube, the wax around the coil will not melt because:
Mercury is a good conductor of heat.State true or false.
The best conductor of heat is
When you pour hot tea suddenly on to a glass tumbler, it cracks. Because:
Cups are not made of metals. The reason is:
Select the odd one out w.r.t. conduction of heat (gold, copper, mercury, cork)
Define insulator of heat.
Select the odd one out w.r.t. conduction of heat (gold, silver, copper, asbestos)
State whether given statement is True or False
Iron is a better conductor of heat than copper
Select the odd one out w.r.t. conduction of heat (wood, paper, plastic, silver)
Which of the following behaves as insulator?
Iron have much lower specific heat than:
Conductors become hot easily because they have:
In general, metals have very low :
Specific heat capacity is ______ for conductors of heat and _______ for insulators of heat.
Conductors require __________ heat energy to get heated.
Graphite is a conductor of electricity because
Examples of non-conductors include
Easy to shape materials like ceramics are used as
Overhead cables are insulated from pylons through
In conductors outer electrons :
In conductors, electrons can flow because their
An insulator is a non-metallic substance which :
Metals are good conductors of electricity than non-metals because:
Poor conductors of electricity consist of
Why is electrical wiring usually made from copper?
Which of the following materials is an electrical conductor?
Which of the following materials is an electrical insulator?
Why are insulators important in an electrical circuit?
Why are electrical plugs made of plastic?
Why is electrical wiring usually covered with a layer of plastic?
A material that does NOT let electricity pass through it is called ...
Materials that allow electrons to flow through them are known as
Which of these is a good electrical conductor?
State whether given statement is True or False
In a superconductor, electricity will flow for a long time and then stop.
State whether given statement is True or False
Innermost electrons are free to move :
When electrons in a material are free to move, the material is:
What is NOT an example of an insulator in the kitchen?
Which of the following would normally be the best conductor?
Which of these could be used to complete an electrical circuit?
Pure Water is an insulator.
The outermost electrons are __________ and are called conduction electrons :
Which material is a best conductor?
Which metal is a good conductor of heat?
Mud houses are cooler in summer and warmer in winter because
In case of conductors and insulators, if an electric field is applied then conduction current density$\vec{(J)}$ is: