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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
- Changing magnetic fields can set up current loops in nearby metal bodies
- Two identical long conducting wires AOB and COD are placed at right angle
- An ideal coil of 10 H is connected in series with a resistance of 5Ω and a battery
- The electromagnetic waves detected using a thermopile and used in physical therapy
- Photocells convert
Topics: Current Electricity (136)
Subject: Physics (2479)
Important MCQs Based on Medical Entrance Examinations To Improve Your NEET Score
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