Match List-I with List-II
| List-I | List-II | ||
| Physical Quantity | Unit | ||
| (A) | Planck’s constant | (I) | \( \mathrm{kg\,m^{2}\,s^{-3}} \) |
| (B) | Stopping potential | (II) | \( \mathrm{kg\,m^{2}\,s^{-2}} \) |
| (C) | Power | (III) | \( \mathrm{kg\,m^{2}\,s^{-1}} \) |
| (D) | Work function | (IV) | \( \mathrm{kg\,m^{2}\,s^{-3}\,A^{-1}} \) |
Choose the correct answer from the options given below:
Answer & explanation
Correct answer: option 2
The correct answer is Option (2) → (A) - (III), (B) - (IV), (C) - (I), (D) - (II)
Reduce each unit to SI base units using \( 1\,\mathrm{J} = 1\,\mathrm{kg\,m^{2}\,s^{-2}} \) and \( 1\,\mathrm{V} = 1\,\mathrm{W\,A^{-1}} \).
(A) Planck’s constant — this matches (III) \( \mathrm{kg\,m^{2}\,s^{-1}} \). From \( E = h\nu \), h is energy multiplied by time: J s.
\( \mathrm{J\,s} = \mathrm{kg\,m^{2}\,s^{-2}}\cdot\mathrm{s} = \mathrm{kg\,m^{2}\,s^{-1}} \)
(B) Stopping potential — this matches (IV) \( \mathrm{kg\,m^{2}\,s^{-3}\,A^{-1}} \). It is a potential, measured in volts, and a volt is a watt per ampere.
\( \mathrm{V} = \mathrm{W\,A^{-1}} = \mathrm{kg\,m^{2}\,s^{-3}\,A^{-1}} \)
(C) Power — this matches (I) \( \mathrm{kg\,m^{2}\,s^{-3}} \). Power is energy per unit time.
\( \mathrm{W} = \mathrm{J\,s^{-1}} = \mathrm{kg\,m^{2}\,s^{-3}} \)
(D) Work function — this matches (II) \( \mathrm{kg\,m^{2}\,s^{-2}} \). The work function is an energy (the minimum energy needed to free an electron), so its SI unit is the joule.