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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
- Two satellites of earth, S₁ and S₂ are moving in the same orbit. The mass of S₁
- In a coil having e.m.f. of 8 V induced for 0.05 s. The value of current changes
- A person holding a rifle (mass of person and rifle together is 100 kg) stands on a smooth
- Two capacitors 3μF and 4μF, are individually charged across a 6 V battery.
- According to Hook’s law of elasticity, if stress is increased, the ratio of stress
Topics: Current Electricity (136)
Subject: Physics (2479)
Important MCQs Based on Medical Entrance Examinations To Improve Your NEET Score
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