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A wire of resistance 4 ohm is stretched to twice its original length. The resistance of stretched wire would be
Options
(a) 4Ω
(b) 8Ω
(c) 16Ω
(d) 2Ω
Correct Answer:
16Ω
Explanation:
Resistance R = ρℓ / A
ℓ’ = 2 ℓ ⇒ A’ = A / 2
R’ = ρ [2 ℓ / (A / 2)] = 4R = 4 × 4Ω = 16Ω
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Topics: Current Electricity
(136)
Subject: Physics
(2479)
Important MCQs Based on Medical Entrance Examinations To Improve Your NEET Score
- A small object of uniform density rolls up a curved surface with an initial velocity
- Two charges each equal to 2µ C are 0.5m apart. If both of them exist inside vacuum
- The wavelength of Kα line in copper is 1.5Å. The ionisation energy of K electron in copper is
- A spherical body of emissivity e=0.6, placed inside a perfectly black body is maintained
- The time period of bar magnet is doubled when magnetic field is reduced
Topics: Current Electricity (136)
Subject: Physics (2479)
Important MCQs Based on Medical Entrance Examinations To Improve Your NEET Score
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