NEET
- Exam
- NEET
- Subject
- Physics
- Chapter
- Units and Dimensions
NEET · Physics · Units and Dimensions
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): Solid angle is a dimensionless physical quantity but it possesses a valid SI unit.
Reason (R): Solid angle is defined as the ratio of intercepted area to the square of the radius, making its dimensional formula , yet it is assigned the supplementary SI unit steradian.
In the light of the above statements, choose the most appropriate answer from the options given below:
Assertion (A): Solid angle is a dimensionless physical quantity but it possesses a valid SI unit.
Reason (R): Solid angle is defined as the ratio of intercepted area to the square of the radius, making its dimensional formula , yet it is assigned the supplementary SI unit steradian.
In the light of the above statements, choose the most appropriate answer from the options given below:
Options
- ABoth Assertion (A) and Reason (R) are true and Reason (R) is the correct explanation of Assertion (A).
- BBoth Assertion (A) and Reason (R) are true but Reason (R) is not the correct explanation of Assertion (A).
- CAssertion (A) is true but Reason (R) is false.
- DAssertion (A) is false but Reason (R) is true.
Correct answer
A. Both Assertion (A) and Reason (R) are true and Reason (R) is the correct explanation of Assertion (A).
Step-by-step solution
Assertion (A) is true because solid angle is a dimensionless quantity (its dimensional formula is ) but it has a supplementary SI unit called the steradian.
Reason (R) is also true and correctly explains Assertion (A). Solid angle is defined as . Since it is the ratio of area () to the square of radius (), the dimensions cancel out, making it dimensionless. Despite this, it is assigned the steradian as a supplementary SI unit to quantify it.
Therefore, both Assertion (A) and Reason (R) are true, and Reason (R) is the correct explanation of Assertion (A).
Answer: Both Assertion (A) and Reason (R) are true and Reason (R) is the correct explanation of Assertion (A).
Reason (R) is also true and correctly explains Assertion (A). Solid angle is defined as . Since it is the ratio of area () to the square of radius (), the dimensions cancel out, making it dimensionless. Despite this, it is assigned the steradian as a supplementary SI unit to quantify it.
Therefore, both Assertion (A) and Reason (R) are true, and Reason (R) is the correct explanation of Assertion (A).
Answer: Both Assertion (A) and Reason (R) are true and Reason (R) is the correct explanation of Assertion (A).