A wire of length lm and radius 0.1 mm has a resistance of 100 Ω. The resistivity of the material is ………………….
A) 3.14 × 106 Ω – m
B) 3.14 × 10-6 Ω – m
C) 3.14 Ω – m
D) 3.14 × 108 Ω – m
1 Answers
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A copper wire has a resistance of \( 0.60 hm \). Anozner copper wire of the samemass as the first one is dou ble in length of the first. Find the resistance of the second wire.
We know that R = ρl/A R ∝ l R1/R2 = l1/l2 Given ∵ l2 = 2l1 R1 = 0.60 hm R2/R1 = l2/l1 R2/R1 = 2l1/l1 R2 = 2 R1 R2 = 2 x 0.60 R2 = 1.2 hm
2 Answers 3 views
The wire of length L and resistance R is stretched so that its radius of cross-section is halved. What is its new resistance?
Correct answer is (D) 16R
2 Answers 1 views
A resistance of `2Omega` is connected across one gap of a metre-bridge(the length of the wire is 100 cm) and an unknown resistance, greater than `2Ome
Answer A) 3 ohm Soln-: 2/x=y/(100-x) 200-2x=xy ......1 After interchanging Y/x+20 = 2/(80-x) 80y-xy=2x+40 .......2 On solving equation 1 and 2 Y=3 ohm
2 Answers 1 views
Two wires of the same material have radii rA and rB respectively. The radius of wire A is twice the radius of wire B.
Correct option is: (D) four times that of A.
2 Answers 1 views
A wire of length ‘L’, radius ‘r’ when stretched with a force ‘F’ changes in length by l’. What will be the change in length of a wire
Correct option is: (B) l
2 Answers 1 views
If work done in stretching a wire by 1 mm is 2 J, the work necessary for stretching another wire of same material, but with double the radius and half
Correct option is: (D) 16
2 Answers 1 views
A uniform wire of resistance 100 Ω is melted and recast into wire of length double that of the
Correct option is A) 400 Ω
2 Answers 1 views
A piece of platinum wire has resistance of 2.5 Ω at 0 °C. If its temperature coefficient of resistance is 4 × 10^-3/°C. Find the resistance
Given: R0 = 2.5 Ω α = 4 × 10-3/°C = 0.004/°C T = 80 °C To find: Resistance at 80 °C (RT) Formula: RT = R0(l + αT) Calculation: From formula, RT = 2.5 [1+ (0.004 × 80)] =...
2 Answers 3 views
The resistivity of Nichrome is 10^-6 Ω-m. The wire of this material has radius of 0.1 mm with resistance 100 Ω, then the length will be
Correct option is: (A) 3.142 m
2 Answers 1 views
Two wires are made of the same material and have the same volume. However, wire 1 has cross-sectional area `A` and wire 2 has cross-sectional area `3A
Correct Answer - 9 9
2 Answers 1 views