The thermo EMF of a thermocouple varies with the temperature θ of the hot junction as E = a θ + b θ 2 in volt where the ratio a b is 700 ° C . If the cold junction is kept at 0 ° C , then neutral temperature is

No neutral temperature is possible for this thermocouple.

EASY

Earn 100

On what factor does thermo emf depend?

Important Questions on Thermal Effect and Chemical Effect of Current

EASY

Physics>Electricity and Magnetism>Thermal Effect and Chemical Effect of Current>Thermoelectricity

A thermocouple produces a thermo-e.m.f. of

40 μ V / {}^{\circ}C

. A thermopile is made by using

150

such thermocouples. The temperatures of the two junctions are

20 ° C

and

40 ° C

. How much thermo-emf will be generated in the thermopile?

MEDIUM

Physics>Electricity and Magnetism>Thermal Effect and Chemical Effect of Current>Thermoelectricity

Represent the union of two sets by Venn diagram for each of the following.

$X = {x | x$ is a prime number between $80$ and $100}$

$Y = {y | y$ is an odd number between $90$ and $100}$

MEDIUM

Physics>Electricity and Magnetism>Thermal Effect and Chemical Effect of Current>Thermoelectricity

Obtain from Faraday's laws of electrolysis the relation between electrochemical equivalent and chemical equivalent of an element.

EASY

Physics>Electricity and Magnetism>Thermal Effect and Chemical Effect of Current>Thermoelectricity

If the temperature of the cold junction of thermocouple is lowered, what will be the effect on its neutral temperature and temperature of inversion?

EASY

Physics>Electricity and Magnetism>Thermal Effect and Chemical Effect of Current>Thermoelectricity

State the factors on which the temperature of inversion of a thermocouple may depend.

EASY

Physics>Electricity and Magnetism>Thermal Effect and Chemical Effect of Current>Thermoelectricity

For a certain thermocouple, the emf

e = a t + b t^{2}

where

t

{}^{\circ}C

is the temperature of the hot junction. The cold junction being at

0 ° C

. If

a = 10 μV {}^{\circ}C^{- 1}

and

b = - 0.02 μV {}^{\circ}C^{- 1}

then the temperature of inversion (in

{}^{\circ}C

) will be:

MEDIUM

Physics>Electricity and Magnetism>Thermal Effect and Chemical Effect of Current>Thermoelectricity

Draw a graph between the temperature and thermo-emf and point out the neutral temperature and temperature of investing in the graph.

MEDIUM

Physics>Electricity and Magnetism>Thermal Effect and Chemical Effect of Current>Thermoelectricity

The thermo EMF of a thermocouple varies with the temperature

θ

of the hot junction as

E = a θ + b θ^{2}

in volt where the ratio

\frac{a}{b}

700 ° C

. If the cold junction is kept at

0 ° C

, then neutral temperature is

MEDIUM

Physics>Electricity and Magnetism>Thermal Effect and Chemical Effect of Current>Thermoelectricity

What is Seebeck effect?

EASY

Physics>Electricity and Magnetism>Thermal Effect and Chemical Effect of Current>Thermoelectricity

State one important difference between Peltiers' effect and Joules' effect.

EASY

Physics>Electricity and Magnetism>Thermal Effect and Chemical Effect of Current>Thermoelectricity

Discuss briefly whether you should use thin wires or thick wires for demonstrating Peltier effect.

EASY

Physics>Electricity and Magnetism>Thermal Effect and Chemical Effect of Current>Thermoelectricity

What is the value of Seebeck coefficient at neutral temperature of a thermocouple?

MEDIUM

Physics>Electricity and Magnetism>Thermal Effect and Chemical Effect of Current>Thermoelectricity

What is Peltier effect ?

EASY

Physics>Electricity and Magnetism>Thermal Effect and Chemical Effect of Current>Thermoelectricity

Give the direction in which thermoelectric current flows at the hot junction of $Cu - Fe$ thermocouple.

MEDIUM

Physics>Electricity and Magnetism>Thermal Effect and Chemical Effect of Current>Thermoelectricity

The expression for thermoemf in a thermocouple is given by the relation

E = 40 θ - \frac{θ^{2}}{20},

when

θ

is the temperature difference of two junctions. For this, the neutral temperature will be

EASY

Physics>Electricity and Magnetism>Thermal Effect and Chemical Effect of Current>Thermoelectricity

Name the temperature for a thermocouple at which its thermoelectric power becomes zero.

EASY

Physics>Electricity and Magnetism>Thermal Effect and Chemical Effect of Current>Thermoelectricity

Two heating elements A and B sealed in identical glass tubes are used as heater. They are put in same quantity of water contained in two identical calorimeters. It is found that when connected in series, element A produces more heat than B but when connected in parallel the element B produces more heat than A. But on measuring the resistance of the elements by a metre bridge, they are found to be equal. Explain.

EASY

Physics>Electricity and Magnetism>Thermal Effect and Chemical Effect of Current>Thermoelectricity

Cotyledons are also called-

MEDIUM

Physics>Electricity and Magnetism>Thermal Effect and Chemical Effect of Current>Thermoelectricity

The thermo e.m.f. of a thermocouple is

25 μ V^{\circ} C^{- 1}

at room temperature. A galvanometer of

40 Ω

resistance, capable of detecting current as low as

10^{- 5} A

, is connected with the thermocouple. The smallest temperature difference that can be identified by this system is

MEDIUM

Physics>Electricity and Magnetism>Thermal Effect and Chemical Effect of Current>Thermoelectricity

State the applications of Seebeck effect.

On what factor does thermo emf depend?

Important Questions on Thermal Effect and Chemical Effect of Current

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