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JEE Physics 2023 Question with Solution

Match List I with List II:

Answer: (1) (A) – III, (B) – I, (C) – II, (D) – IV\text{(1) (A) – III, (B) – I, (C) – II, (D) – IV}

  • A

    (A) – III, (B) – I, (C) – II, (D) – IV\text{(A) – III, (B) – I, (C) – II, (D) – IV}

  • B

    (A) – I, (B) – II, (C) – IV, (D) – III\text{(A) – I, (B) – II, (C) – IV, (D) – III}

  • C

    (A) – II, (B) – I, (C) – IV, (D) – III\text{(A) – II, (B) – I, (C) – IV, (D) – III}

  • D

    (A) – III, (B) – I, (C) – IV, (D) – II\text{(A) – III, (B) – I, (C) – IV, (D) – II}

Answer

Correct answer:A

Step-by-step solution

Standard Method

Given: A matching question on dimensional formulas.

Find: The correct option that matches each quantity with its dimensional formula.

Use the physical definition of each quantity and write its dimensional formula.

For pressure gradient:

ΔPΔx=[M1L1T2][L]=[M1L2T2]\frac{\Delta P}{\Delta x} = \frac{[M^1L^{-1}T^{-2}]}{[L]} = [M^1L^{-2}T^{-2}]

For energy density:

EnergyVolume=[M1L2T2][L3]=[M1L1T2]\frac{\text{Energy}}{\text{Volume}} = \frac{[M^1L^2T^{-2}]}{[L^3]} = [M^1L^{-1}T^{-2}]

For electric field:

ForceCharge=[M1L1T2][A1T1]=[M1L1T3A1]\frac{\text{Force}}{\text{Charge}} = \frac{[M^1L^1T^{-2}]}{[A^1T^1]} = [M^1L^1T^{-3}A^{-1}]

For latent heat:

Heat energyMass=[M1L2T2][M]=[M0L2T2]\frac{\text{Heat energy}}{\text{Mass}} = \frac{[M^1L^2T^{-2}]}{[M]} = [M^0L^2T^{-2}]

Comparing these with the given lists, the correct matching is (A) – III, (B) – I, (C) – II, (D) – IV.

Therefore, the correct option is A.

Common mistakes

  • Confusing pressure with pressure gradient. Pressure has dimensions [M1L1T2][M^1L^{-1}T^{-2}], but pressure gradient is pressure divided by length, so one extra L1L^{-1} must appear. Always divide by the spatial coordinate explicitly.

  • Using energy density as energy per area instead of energy per volume. The correct expression is energy divided by volume, so divide by [L3][L^3], not [L2][L^2].

  • Writing electric field dimensions incorrectly by forgetting that charge has dimensions [AT][AT]. Since E=FqE = \frac{F}{q}, divide force by [A1T1][A^1T^1] to get [M1L1T3A1][M^1L^1T^{-3}A^{-1}].

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