In a potentiometer, the sensitivity can be increased by: MCQ with Answer and Explanation

In a potentiometer, the sensitivity can be increased by:
A. Increasing the length of the wire
B. Increasing the current in the primary circuit
C. Decreasing the length of the wire
D. Using a thicker wire
Answer: Option A
Solution (By JKExamLibrary)
Potentiometer sensitivity (ability to detect small EMF changes) increases with longer wire because potential gradient (V/cm) decreases, allowing finer measurement of balancing length. Sensitivity ∝ length of wire. Decreasing length (B) reduces sensitivity; increasing current (C) increases potential gradient, reducing sensitivity; thicker wire (D) reduces resistance but doesn't directly affect sensitivity if current adjusted. Memory tip: 'Longer potentiometer wire ⇒ smaller potential gradient ⇒ higher sensitivity'. This experimental physics concept is frequently tested in competitive exams. Always link sensitivity to potential gradient: smaller gradient allows detection of smaller voltage differences.

This question belongs to: Science Physics

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Question #1 Report Error
A vernier caliper has 20 divisions on vernier scale matching 19 main scale divisions. If main scale division is 1 mm, least count is:
A. 0.1 mm
B. 0.01 mm
C. 0.5 mm
D. 0.05 mm

Correct Answer: Option D


Explanation:
Least count = 1 MSD - 1 VSD. 20 VSD = 19 MSD ⇒ 1 VSD = 19/20 mm = 0.95 mm. LC = 1 - 0.95 = 0.05 mm. Formula: LC = MSD/n where n = vernier divisions. Memory tip: LC = smallest measurable difference = main scale value/vernier divisions. Essential for practical physics questions in competitive exams.

This question belongs to: Science Physics
Question #2 Report Error
The specific heat capacity of a substance is defined as the amount of heat required to:
A. Raise the temperature of 1 kg of the substance by 1°C
B. Melt 1 kg of the substance at its melting point
C. Raise the temperature of 1 g of the substance by 1°C
D. Vaporize 1 kg of the substance at its boiling point

Correct Answer: Option A


Explanation:
Specific heat capacity c is defined as heat required to raise temperature of unit mass (1 kg in SI) by 1°C (or 1 K). Formula: Q = mcΔT. Option D describes specific heat in cgs units (cal/g°C), but SI definition uses kg. Options A and C describe latent heats. Memory aid: 'Specific heat = per kg per degree'. This precise definition is crucial for calorimetry problems. Competitive exams often test unit awareness (kg vs g) to distinguish careful students. Always note the mass unit in the definition context.

This question belongs to: Science Physics
Question #3 Report Error
The colour of light with minimum wavelength in visible spectrum is
A. Yellow
B. Green
C. Red
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Correct Answer: Option D


Explanation:
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This question belongs to: Science Physics