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Directions : In the following questions, A statement of Assertion (A) is followed by a statement of Reason (R). Mark the correct choice as.
Assertion (A): The resistivity of a semiconductor decreases with temperature.
Reason (R): The atoms of a semiconductor vibrate with larger amplitude at higher temperature there by increasing it's resistivity.
- a)Both A and R are true and R is the correct explanation of A
- b)Both A and R are true but R is NOT the correct explanation of A
- c)A is true but R is false
- d)Both A and R are incorrect
Correct answer is option 'D'. Can you explain this answer?
Verified Answer
Directions : In the following questions, A statement of Assertion (A) ...
Conductors – They are materials that have a lot of free electrons and as the flow of current is essentially the flow of electrons in a material, thus, we say that conductors have very less resistance and can conduct more current. Example – Metals, tap water, etc.
Insulators - They are materials that have no free electrons, thus, we say that insulators have very high resistance and do not conduct electricity. Example - Wood, plastic, etc.
Semiconductors – Semiconductors lie somewhere in between conductors and insulators. They have few free electrons that can lead to the flow of current. Semiconductors are essentially a crystal lattice in which the atoms are grouped close together. Example – Silicon, Gallium, etc.
Semiconductors are very unique, their ability of conducting electricity can change when impurities are introduced in the crystal lattice (generally a small percentage of another element is added to the semiconductor).
The free electrons that can conduct electricity are said to be in conduction band, basically all the electrons in the conduction band have enough energy to move away from their atoms and conduct electricity.
Now, increasing the temperature will increase the energy of more electrons, increasing the total number of free electrons in the conduction band, this will result in increase in conductivity and a decrease in resistivity.
Thus, both the assertion and the reasons are false as increase in temperature leads to a decrease in resistivity.
Insulators - They are materials that have no free electrons, thus, we say that insulators have very high resistance and do not conduct electricity. Example - Wood, plastic, etc.
Semiconductors – Semiconductors lie somewhere in between conductors and insulators. They have few free electrons that can lead to the flow of current. Semiconductors are essentially a crystal lattice in which the atoms are grouped close together. Example – Silicon, Gallium, etc.
Semiconductors are very unique, their ability of conducting electricity can change when impurities are introduced in the crystal lattice (generally a small percentage of another element is added to the semiconductor).
The free electrons that can conduct electricity are said to be in conduction band, basically all the electrons in the conduction band have enough energy to move away from their atoms and conduct electricity.
Now, increasing the temperature will increase the energy of more electrons, increasing the total number of free electrons in the conduction band, this will result in increase in conductivity and a decrease in resistivity.
Thus, both the assertion and the reasons are false as increase in temperature leads to a decrease in resistivity.
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Most Upvoted Answer
Directions : In the following questions, A statement of Assertion (A) ...
Assertion and Reasoning
Assertion (A): The resistivity of a semiconductor decreases with temperature.
Reason (R): The atoms of a semiconductor vibrate with larger amplitude at higher temperature, thereby increasing its resistivity.
Explanation
Semiconductors are materials that have resistivity between conductors and insulators. The resistivity of a semiconductor decreases with an increase in temperature. The following is an explanation of why the assertion is true and the reasoning is false:
Assertion (A) is true because:
- The resistivity of a semiconductor depends on the number of charge carriers available for conduction.
- In a semiconductor, the number of charge carriers increases with temperature due to an increase in the number of thermally generated charge carriers.
- As a result, the resistivity of a semiconductor decreases with temperature.
Reasoning (R) is false because:
- The increase in resistivity with temperature is due to an increase in the scattering of charge carriers by the thermally activated lattice vibrations in the crystal.
- As the temperature increases, the amplitude of the lattice vibrations increases, leading to more scattering of charge carriers and an increase in resistivity.
- Therefore, the reasoning is incorrect because the increase in resistivity is not due to an increase in atomic vibrations but due to an increase in scattering.
Conclusion
Hence, the correct option is (D) A is false, and R is true.
Assertion (A): The resistivity of a semiconductor decreases with temperature.
Reason (R): The atoms of a semiconductor vibrate with larger amplitude at higher temperature, thereby increasing its resistivity.
Explanation
Semiconductors are materials that have resistivity between conductors and insulators. The resistivity of a semiconductor decreases with an increase in temperature. The following is an explanation of why the assertion is true and the reasoning is false:
Assertion (A) is true because:
- The resistivity of a semiconductor depends on the number of charge carriers available for conduction.
- In a semiconductor, the number of charge carriers increases with temperature due to an increase in the number of thermally generated charge carriers.
- As a result, the resistivity of a semiconductor decreases with temperature.
Reasoning (R) is false because:
- The increase in resistivity with temperature is due to an increase in the scattering of charge carriers by the thermally activated lattice vibrations in the crystal.
- As the temperature increases, the amplitude of the lattice vibrations increases, leading to more scattering of charge carriers and an increase in resistivity.
- Therefore, the reasoning is incorrect because the increase in resistivity is not due to an increase in atomic vibrations but due to an increase in scattering.
Conclusion
Hence, the correct option is (D) A is false, and R is true.
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Directions : In the following questions, A statement of Assertion (A) is followed by a statement of Reason (R). Mark the correct choice as.Assertion (A): The resistivity of a semiconductor decreases with temperature.Reason (R): The atoms of a semiconductor vibrate with larger amplitude at higher temperature there by increasing its resistivity.a)Both A and R are true and R is the correct explanation of Ab)Both A and R are true but R is NOT the correct explanation of Ac)A is true but R is falsed)Both A and R are incorrectCorrect answer is option 'D'. Can you explain this answer?
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Directions : In the following questions, A statement of Assertion (A) is followed by a statement of Reason (R). Mark the correct choice as.Assertion (A): The resistivity of a semiconductor decreases with temperature.Reason (R): The atoms of a semiconductor vibrate with larger amplitude at higher temperature there by increasing its resistivity.a)Both A and R are true and R is the correct explanation of Ab)Both A and R are true but R is NOT the correct explanation of Ac)A is true but R is falsed)Both A and R are incorrectCorrect answer is option 'D'. Can you explain this answer? for Class 12 2024 is part of Class 12 preparation. The Question and answers have been prepared according to the Class 12 exam syllabus. Information about Directions : In the following questions, A statement of Assertion (A) is followed by a statement of Reason (R). Mark the correct choice as.Assertion (A): The resistivity of a semiconductor decreases with temperature.Reason (R): The atoms of a semiconductor vibrate with larger amplitude at higher temperature there by increasing its resistivity.a)Both A and R are true and R is the correct explanation of Ab)Both A and R are true but R is NOT the correct explanation of Ac)A is true but R is falsed)Both A and R are incorrectCorrect answer is option 'D'. Can you explain this answer? covers all topics & solutions for Class 12 2024 Exam. Find important definitions, questions, meanings, examples, exercises and tests below for Directions : In the following questions, A statement of Assertion (A) is followed by a statement of Reason (R). Mark the correct choice as.Assertion (A): The resistivity of a semiconductor decreases with temperature.Reason (R): The atoms of a semiconductor vibrate with larger amplitude at higher temperature there by increasing its resistivity.a)Both A and R are true and R is the correct explanation of Ab)Both A and R are true but R is NOT the correct explanation of Ac)A is true but R is falsed)Both A and R are incorrectCorrect answer is option 'D'. Can you explain this answer?.
Directions : In the following questions, A statement of Assertion (A) is followed by a statement of Reason (R). Mark the correct choice as.Assertion (A): The resistivity of a semiconductor decreases with temperature.Reason (R): The atoms of a semiconductor vibrate with larger amplitude at higher temperature there by increasing its resistivity.a)Both A and R are true and R is the correct explanation of Ab)Both A and R are true but R is NOT the correct explanation of Ac)A is true but R is falsed)Both A and R are incorrectCorrect answer is option 'D'. Can you explain this answer? for Class 12 2024 is part of Class 12 preparation. The Question and answers have been prepared according to the Class 12 exam syllabus. Information about Directions : In the following questions, A statement of Assertion (A) is followed by a statement of Reason (R). Mark the correct choice as.Assertion (A): The resistivity of a semiconductor decreases with temperature.Reason (R): The atoms of a semiconductor vibrate with larger amplitude at higher temperature there by increasing its resistivity.a)Both A and R are true and R is the correct explanation of Ab)Both A and R are true but R is NOT the correct explanation of Ac)A is true but R is falsed)Both A and R are incorrectCorrect answer is option 'D'. Can you explain this answer? covers all topics & solutions for Class 12 2024 Exam. Find important definitions, questions, meanings, examples, exercises and tests below for Directions : In the following questions, A statement of Assertion (A) is followed by a statement of Reason (R). Mark the correct choice as.Assertion (A): The resistivity of a semiconductor decreases with temperature.Reason (R): The atoms of a semiconductor vibrate with larger amplitude at higher temperature there by increasing its resistivity.a)Both A and R are true and R is the correct explanation of Ab)Both A and R are true but R is NOT the correct explanation of Ac)A is true but R is falsed)Both A and R are incorrectCorrect answer is option 'D'. Can you explain this answer?.
Solutions for Directions : In the following questions, A statement of Assertion (A) is followed by a statement of Reason (R). Mark the correct choice as.Assertion (A): The resistivity of a semiconductor decreases with temperature.Reason (R): The atoms of a semiconductor vibrate with larger amplitude at higher temperature there by increasing its resistivity.a)Both A and R are true and R is the correct explanation of Ab)Both A and R are true but R is NOT the correct explanation of Ac)A is true but R is falsed)Both A and R are incorrectCorrect answer is option 'D'. Can you explain this answer? in English & in Hindi are available as part of our courses for Class 12.
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