# Thermal and Chemical Effects of Electric Current Obj-1 HC Verma Solutions Vol-2 Class-12 Ch-33

Thermal and Chemical Effects of Electric Current Obj-1 HC Verma Solutions Vol-2 Class-12 Ch-33 Concept of Physics for Class-12. Step by Step Solutions of Objective -1 (MCQ-1) Questions of Chapter-33 Thermal and Chemical Effects of Electric Current (Concept of Physics) .Visit official Website CISCE for detail information about ISC Board Class-11 Physics.

## Thermal and Chemical Effects of Electric Current Obj-1 HC Verma Solutions Vol-2 Class-12 Ch-33

 Board ISC and other board Publications Bharti Bhawan Publishers Chapter-33 Thermal and Chemical Effects of Electric Current Class 12 Vol 2nd writer HC Verma Book Name Concept of Physics Topics Solution of Objective-1 (MCQ-1) Questions Page-Number 217, 218

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Thermal and Chemical Effects of Electric Current Obj-1 (MCQ-1) Questions

### HC Verma Solutions of Ch-33  Vol-2 Concept of Physics for Class-12

(Page-217)

#### Question-1 :-

Which of the following plots may represent the thermal energy produced in a resistor in a given time as a function of the electric current?

(Figure 33-Q2)

Answer 1 :-

The option (a) is correct
Explanation:
When current passes through a resistor, the heat produced,
H = I2Rt,
where I = current
R = resistance of the resistor
t = time for which current is flowing
This relation shows that the heat produced for a given time in a resistor varies with the square of current flowing through it. Hence, the plot between H vs I should be a parabola symmetric along the H axis, which is represented by curve a.

#### Question 2 :-

A constant current i is passed through a resistor. Taking the temperature coefficient of resistance into account, indicate which of the plots shown in the figure best represents the rate of production of thermal energy in the resistor.

(Figure 33-Q3)

Answer 2 :-

The option (d) is correct
Explanation:

When current passes through a resistor, the temperature of the resistor increases due to the heat produced in it.
H = i2Rt,

where i = current flowing through the resistor

R = resistance of the resistor

t = time for which the current is flowing

With the increase in the temperature of the resistor, its resistance is also increased. The rate of production of thermal energy in the resistor of the circuit is given by the following relation-

where i = current flowing through the resistor

R = resistance of the resistor

Rate of production of thermal energy in the resistor is directly proportional to the resistance. So, due to increase in resistance, dU/dt also increases linearly, which is best represented by plot d.

### Thermal and Chemical Effects of Electric Current Obj-1 (MCQ-1) Questions

HC Verma Solutions of Ch-33  Vol-2 Concept of Physics for Class-12

(Page-218)

#### Question 3 :-

Consider the following statements regarding a thermocouple.
(A) The neutral temperature does not depend on the temperature of the cold junction.
(B) The inversion temperature does not depend on the temperature of the cold junction.

(a) A and B are correct

(b) A is correct but B is wrong

(c) B is correct but A is wrong

(d) A and B are wrong

Answer 3 :-

The option (b) A is correct but B is wrong is correct
Explanation:

The value of neutral temperature is constant for a thermocouple. It depends on the nature of materials and is independent of the temperature of the cold junction. Inversion temperature depends on the temperature of the cold junction, as well as the nature of the material.

#### Question 5 :-

Consider the following statements.
(A) Free-electron density is different in different metals.
(B) Free-electron density in a metal depends on temperature.
Seebeck Effect is caused.

(a) due to both A and B

(b) due to A but not due to B

(c) due to B but not due to A

(d) neither due to A nor due to B

Answer 5 :-

The option (a) due to both A and B is correct
Explanation:

In Seebeck Effect, a temperature difference between two dissimilar electrical conductors produces a potential difference across the junctions of the two different metals. The cause of this potential difference is the diffusion of free electrons from a high electron-density region to a low electron-density region. The free electron-density of the electrons is different in different metals and changes with change in temperature.

#### Question 6 :-

Consider the following statements.
(A) Free-electron density is different in different metals.
(B) Free-electron density in a metal depends on temperature.

Peltier Effect is caused .

(a) due to both A and B

(b) due to A but not due to B

(c) due to B but not due to A

(d) neither due to A nor due to B

Answer 6 :-

The option (b) due to A but not due to B is correct
Explanation:

In Peltier Effect, one of the junctions gets heated up and the other cools down when electric current is maintained in a circuit of material consisting of two dissimilar conductors.

#### Question 7 :-

Consider the following statements.
(A) Free-electron density is different in different metals.
(B) Free-electron density in a metal depends on temperature.

Thomson Effect is caused.

(a) due to both A and B

(b) due to A but not due to B

(c) due to B but not due to A

(d) neither due to A nor due to B

Answer 7 :-

The option (c) due to B but not due to A is correct
Explanation:

If a metallic conductor has non-uniform temperature distribution along its length, the density of the free electrons is different for different sections. The electrons diffuse from the sections with higher concentration to those with lower concentration of free electrons.

#### Question 8 :-

Faraday constant.

(a) depends on the amount of the electrolyte

(b) depends on the current in the electrolyte

(c) is a universal constant

(d) depends on the amount of charge passed through the electrolyte

Answer 8 :-

The option (c) is a universal constant is correct
Explanation:

Faraday’s constant is a universal constant. Its value is 9.6845×107 C/kg. It does not depend on the amount of the electrolyte, current in the electrolyte and on the amount of charge passed through the electrolyte.

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