JEE Mains · Physics · STD 11 - Units,dimensions and measurement
- JEE Mains 2020
- Medium
- MCQ
If momentum \((P),\) area \((A)\) and time \((T)\) are taken to be the fundamental quantities then the dimensional formula for energy is :
Pick an option to check your answer.
Answer & Solution
Correct Answer
(B) \(\left[ PA ^{1 / 2} T ^{-1}\right]\)
Step-by-step Solution
Detailed explanation
Let \([ E ]=[ P ]^{ x }[ A ]^{ y }[ T ]^{z}\)
\(ML ^{2} T ^{-2}=\left[ MLT ^{-1}\right]^{ x }\left[ L ^{2}\right] y [ T ]^{z}\)
\(ML ^{2} T ^{-2}= M ^{ x } L ^{ x +2 y } T ^{- x +z}\)
\(\rightarrow x =1\)
\(\rightarrow x +2 y =2\)
\(1+2 y =2\)
\(y =\frac{1}{2}\)
\(\rightarrow- x + z =-2\)
\(-1+ z =-2\)
\(z =-1\)
\([ E ]=\left[ P A ^{1 / 2} T ^{-1}\right]\)
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