NEET
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- NEET
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- Physics
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- Capacitance
NEET · Physics · Capacitance
Given below are two statements: one is labelled as Assertion (A)...
Given below are two statements: one is labelled as Assertion (A) and the other is labelled as Reason (R).
Assertion (A): When a dielectric slab () of thickness is introduced between the plates of an isolated charged parallel plate capacitor, the potential difference between the plates decreases.
Reason (R): For an isolated charged capacitor, the electric field in the air gap between the plates remains unchanged upon the introduction of the dielectric slab.
In the light of the above statements, choose the most appropriate answer from the options given below:
Assertion (A): When a dielectric slab () of thickness is introduced between the plates of an isolated charged parallel plate capacitor, the potential difference between the plates decreases.
Reason (R): For an isolated charged capacitor, the electric field in the air gap between the plates remains unchanged upon the introduction of the dielectric slab.
In the light of the above statements, choose the most appropriate answer from the options given below:
Options
- ABoth Assertion and Reason are true and Reason is the correct explanation of Assertion.
- BBoth Assertion and Reason are true but Reason is not the correct explanation of Assertion.
- CAssertion is true but Reason is false.
- DAssertion is false but Reason is true.
Correct answer
B. Both Assertion and Reason are true but Reason is not the correct explanation of Assertion.
Step-by-step solution
For an isolated charged capacitor, the charge on the plates remains constant.
The electric field in the air gap is , which remains unchanged since is constant. Thus, the Reason is true.
Inside the dielectric slab, the electric field is reduced to . The new potential difference between the plates is .
Since , the new potential difference is less than the original potential difference . Thus, the Assertion is true.
However, the decrease in potential difference is due to the reduction of the electric field inside the dielectric slab, not because the field in the air gap remains unchanged. Therefore, both Assertion and Reason are true, but the Reason is not the correct explanation of the Assertion.
Answer: Both Assertion and Reason are true but Reason is not the correct explanation of Assertion.
The electric field in the air gap is , which remains unchanged since is constant. Thus, the Reason is true.
Inside the dielectric slab, the electric field is reduced to . The new potential difference between the plates is .
Since , the new potential difference is less than the original potential difference . Thus, the Assertion is true.
However, the decrease in potential difference is due to the reduction of the electric field inside the dielectric slab, not because the field in the air gap remains unchanged. Therefore, both Assertion and Reason are true, but the Reason is not the correct explanation of the Assertion.
Answer: Both Assertion and Reason are true but Reason is not the correct explanation of Assertion.