Question:medium

List-I presents some physical quantities and List-II presents their dimensions. Match the two lists appropriately. 

Updated On: Apr 9, 2026
  • A\(\rightarrow\)(3); B\(\rightarrow\)(4); C\(\rightarrow\)(2); D\(\rightarrow\)(1)
  • A\(\rightarrow\)(3); B\(\rightarrow\)(1); C\(\rightarrow\)(4); D\(\rightarrow\)(2)
  • A\(\rightarrow\)(2); B\(\rightarrow\)(3); C\(\rightarrow\)(4); D\(\rightarrow\)(1)
  • A\(\rightarrow\)(4); B\(\rightarrow\)(3); C\(\rightarrow\)(1); D\(\rightarrow\)(2)
Show Solution

The Correct Option is B

Solution and Explanation

Step 1: Understanding the Question:
The problem requires matching physical quantities with their correct dimensional formulas. Dimension of a quantity is the power to which fundamental units (Mass [M], Length [L], Time [T], Current [I]) are raised to represent it.
Step 2: Key Formula or Approach:
We use basic physical definitions to derive dimensions:
Energy (\(E\)) = \([ML^{2}T^{-2}]\)
Electric Potential (\(V\)) = \(\frac{\text{Work}}{\text{Charge}}\)
Planck's constant (\(h\)) from \(E = hf\)
Step 3: Detailed Explanation:
(A) Work function (f): It is a measure of energy required to remove an electron. Its dimensions are the same as energy:
\[ [f] = [ML^{2}T^{-2}] \Rightarrow \text{Matches (3)} \]
(B) Stopping potential (\(v_{s}\)): It is electric potential. Potential = \(\frac{\text{Work}}{\text{Charge}}\).
Charge (\(q\)) = \(Current \times Time = [IT]\).
\[ [v_{s}] = \frac{[ML^{2}T^{-2}]}{[IT]} = [ML^{2}T^{-3}I^{-1}] \Rightarrow \text{Matches (1)} \]
(C) Planck's constant (h): From the relation \(E = hf \Rightarrow h = \frac{E}{f}\).
Frequency (\(f\)) has dimensions \([T^{-1}]\).
\[ [h] = \frac{[ML^{2}T^{-2}]}{[T^{-1}]} = [ML^{2}T^{-1}] \Rightarrow \text{Matches (4)} \]
(D) Frequency (f): It is the number of oscillations per unit time.
\[ [f] = \frac{1}{[T]} = [T^{-1}] \Rightarrow \text{Matches (2)} \]
Step 4: Final Answer:
The matching pairs are: A-3, B-1, C-4, and D-2. This corresponds to Option (B).
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