Heat current can be defined as the rate at which the heat is transferred per unit time. As it is the rate of energy over time, so it is represented in the SI unit of joule per second or Watt(W). Heat is something that flows through objects with help of conduction imparting energy to the neighbouring particles.

The rate of flow of heat through a copper rod with temperature difference 30 ° C is 1500 c a l / s . Find the thermal resistance of copper rod.

Given that, d Q d t = 1500 c a l / s ∆ T = 30 ° C = 30 K We know that, d Q d t = ∆ T R t h ⇒ 1500 = 30 R t h ⇒ R t h = 30 1500 ⇒ R t h = 0 . 02 K s / c a l Hence, thermal resistance is 0 . 02 K s / c a l .

EASY

Earn 100

Define heat current.

Important Questions on Thermal Phenomena

MEDIUM

Physical Science>Physics>Thermal Phenomena>Thermal Conduction

What is thermal conductivity? What is its SI unit?

EASY

Physical Science>Physics>Thermal Phenomena>Thermal Conduction

State whether the following statement is true or false:
“The constituent particles of a material change position during conduction of heat through it.”

EASY

Physical Science>Physics>Thermal Phenomena>Thermal Conduction

All liquids are poor conductors of heat except _____.

MEDIUM

Physical Science>Physics>Thermal Phenomena>Thermal Conduction

Explain the term 'steady state'.

EASY

Physical Science>Physics>Thermal Phenomena>Thermal Conduction

K =

thermal conductivity, the value of thermal resistivity

EASY

Physical Science>Physics>Thermal Phenomena>Thermal Conduction

For an ideal _____ thermal conductivity is infinite.

EASY

Physical Science>Physics>Thermal Phenomena>Thermal Conduction

A rod of length

ℓ

and cross section area

A

has a variable thermal conductivity given by

k = α T

, where

α

is positive constant and

T

is temperature in kelvin. Two ends of the rod are maintained at temperatures

T_{1}

and

T_{2} (T_{1} > T_{2})

. Heat current flowing through the rod will be

EASY

Physical Science>Physics>Thermal Phenomena>Thermal Conduction

Conduction of heat is possible in vacuum.

HARD

Physical Science>Physics>Thermal Phenomena>Thermal Conduction

A conducting cylindrical rod of uniform cross-sectional area is kept between two large chambers which are at temperatures $100 ° C$ and $0 ° C$ , respectively. The conductivity of the rod increases with $x$ , where $x$ is distance from $100 ° C$ end. The temperature profile of the rod in steady-state will be as:

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EASY

Physical Science>Physics>Thermal Phenomena>Thermal Conduction

Name the non-metal which helps in conduction of heat.

EASY

Physical Science>Physics>Thermal Phenomena>Thermal Conduction

The rate of flow of heat through a copper rod with temperature difference

30 ° C

1500 c a l / s

. Find the thermal resistance of copper rod.

EASY

Physical Science>Physics>Thermal Phenomena>Thermal Conduction

In case of an ideal insulator, the thermal conductivity

K

EASY

Physical Science>Physics>Thermal Phenomena>Thermal Conduction

\frac{θ_{1} - θ_{2}}{d}

is the terms refers to _____.

EASY

Physical Science>Physics>Thermal Phenomena>Thermal Conduction

An object contains more heat’- is it a right statement? If not why?

EASY

Physical Science>Physics>Thermal Phenomena>Thermal Conduction

Thermal resistivity is analogous to _____.

EASY

Physical Science>Physics>Thermal Phenomena>Thermal Conduction

Which materials can be used as thermal insulators and why?

EASY

Physical Science>Physics>Thermal Phenomena>Thermal Conduction

Dependence of heat current is characterised by

EASY

Physical Science>Physics>Thermal Phenomena>Thermal Conduction

A bimetallic strip, made of brass and iron, after heating

HARD

Physical Science>Physics>Thermal Phenomena>Thermal Conduction

Liquid water coats an active (growing) icicle and extends up a short, narrow tube along the central axis. Because the water-ice interface must have a temperature of $0 ° C$ , the water in the tube cannot lose energy through the sides of the icicle or down through the tip because there is no temperature change in those directions. It can lose energy and freeze only by sending energy up (through distance $L$ ) to the top of the icicle, where the temperature $T_{r}$ can be below $0 ° C .$ Take $L = 0.10 m$ and $T_{r} = - 5 ° C .$ Assume that the central tube and the upward conduction path both have cross-sectional area $A = 0.5 m^{2} .$ The thermal conductivity of ice is $0.40 W / m \cdot K,$ latent heat of fusion is $L_{F} = 4.0 \times 10^{5} J / k$ and the density of liquid water is $1000 kg / m^{3}$ .

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The rate at which mass converted from liquid to ice at the top of the central tube is:

EASY

Physical Science>Physics>Thermal Phenomena>Thermal Conduction

Explain the term thermal resistance. State its SI unit arid dimensions.

Define heat current.

Important Questions on Thermal Phenomena

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