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A wire of a certain material is stretched slowly by ten percent. Its new resistance and specific resistance become respectively
Options
(a) both remain the same
(b) 1.1 times, 1.1 times
(c) 1.2 times, 1.1 times
(d) 1.21 times, same
Correct Answer:
1.21 times, same
Explanation:
Δl / l = 0.1 , Therefore, l = 1.1 but the area also decreases by 0.1.
mass = ρlA = Vρ. In l + In A = 1n mass.
.·. Δl / l = ΔA / A = 0 ⇒ Δl / l = -ΔA / A
Length increases by 0.1, resistance increases, area decreases by 0.1, then also resistance will increase. Total increase in resistance is approximately 1.2 times, due to increase in length and decrease in area. But specific resistance does not change.
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Topics: Current Electricity
(136)
Subject: Physics
(2479)
Important MCQs Based on Medical Entrance Examinations To Improve Your NEET Score
- From a disc of radius R, a concentric circular portion of radius r is cut-out so
- A hemispherical bowl of radius R is rotating about its axis of symmetry
- If 75% of the radioactive reaction is completed in 2 hrs, what would be
- The ‘rad’ is the correct unit used to report the measurement of
- In the series resonance the value of impedence is 3 Ω and the resistance is 4Ω,
Topics: Current Electricity (136)
Subject: Physics (2479)
Important MCQs Based on Medical Entrance Examinations To Improve Your NEET Score
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