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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
- A charge Q is uniformly distributed over a large plastic plate. The electric field
- An object is 8 cm high. It is desired to form a real image 4 cm high at 60 cm from
- A thermocouple of negligible resistance produces an e.m.f. of 40 µV/⁰C in the linear range
- Two radiations of photons energies 1 eV and 2.5 eV, successively
- A system consists of three masses m₁, m₂ and m₃ connected by a string passing
Topics: Current Electricity (136)
Subject: Physics (2479)
Important MCQs Based on Medical Entrance Examinations To Improve Your NEET Score
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