A wire of a certain material is stretched slowly by ten percent. Its new resistance

⇦

⇨

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.

Related Questions:

1. A metal plate weighing 750g is to be electroplated with 0.05% of its weight of silver.
2. A magnetic field of 1600 A/m produces a magnetic flux of 2.4 x 10⁻⁵ Wb
3. A tangent galvanometer has a coil of 50 turns and a radius of 20 cm. The horizontal
4. Three objects A,B and C are kept in a straight line on a frictionless horizontal surface
5. Two bodies A(of mass 1kg) and B(of mass 3 kg) are dropped from heights of 16m and 25m

Topics: Current Electricity (136)
Subject: Physics (2479)

---

Important MCQs Based on Medical Entrance Examinations To Improve Your NEET Score

18000+ students are using NEETLab to improve their score. What about you?

Solve Previous Year MCQs, Mock Tests, Topicwise Practice Tests, Identify Weak Topics, Formula Flash cards and much more is available in NEETLab Android App to improve your NEET score.

---

Share this page with your friends