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Question #42738

Difficulty: 8/10 | 🟢 Free

The Question

A specialized liquid-electrolyte battery of EMF E=12 VE = 12 \text{ V} is connected across an external resistor R=4 ΩR = 4 \ \Omega. Due to pressure-induced viscosity changes, the average ion mobility in the electrolyte is inversely proportional to the hydrostatic pressure difference ΔP\Delta P between the bottom and top of the electrolyte column. Consequently, the internal resistance rr of this battery depends on ΔP\Delta P. When the battery is at rest on the ground, its internal resistance is r0=2 Ωr_0 = 2 \ \Omega. The entire setup is placed inside an elevator. If the elevator accelerates upwards with a constant acceleration a=5 m/s2a = 5 \text{ m/s}^2, calculate the terminal voltage across the battery. (Assume the density of the electrolyte and the height of the column remain constant, and take g=10 m/s2g = 10 \text{ m/s}^2).

Options

  • A.

    487 V\frac{48}{7} \text{ V}

  • B.

    8 V8 \text{ V}

  • C.

    485 V\frac{48}{5} \text{ V}

  • D.

    9 V9 \text{ V}

Check Your Answer

Correct Answer

Step-by-Step Solution

Explanation

How the Examiner Thinks

Variable_Constraint

Develop pure symbolic logic skills by mastering algebraic constraints without relying on numerical data.

Concepts Behind This Question

Internal Resistance Variation|Apparent Weight in Accelerating Elevators|Work-Energy Theorem

Why This Question Is Tricky

Common Mistakes

This question tests the synthesis of non-inertial mechanics and electrodynamics.

Students often fall into the trap of treating a battery's internal resistance as a fixed constant, ignoring the mechanical environment of the liquid electrolyte.

By introducing a pressure-dependent mobility, the problem forces the application of the effective gravitational field (geff=g+ag_{\text{eff}} = g + a) in an accelerating reference frame.

Common errors include ignoring the pseudo-force entirely (yielding 8 V), applying the pseudo-force in the wrong direction by subtracting acceleration (yielding 48/5 V), or incorrectly inverting the proportionality between resistance and pressure (yielding 9 V).

Quick Facts About This Question

Question Information

SubjectPhysics
ChapterCurrent Electricity - Class 12
ConceptInternal Resistance Variation
Difficulty8
Cognitive Load7
Target Solve Time160 sec
AccessFree