Advertisements
Advertisements
Question
A negligibly small current is passed through a wire of length 15 m and uniform cross-section 6.0 × 10−7 m2, and its resistance is measured to be 5.0 Ω. What is the resistivity of the material at the temperature of the experiment?
Advertisements
Solution
Given: Length of the wire, l = 15 m
Area of cross-section of the wire, A = 6.0 × 10−7 m2
Resistance of the material of the wire, R = 5.0 Ω
To find: Resistivity of the material of the wire ρ = ?
Formula: Resistance is related to resistivity as,
R = `ρ l/A`
ρ = `(RA)/l`
= `(5.0 xx 6.0 xx 10^-7)/15`
= `(30 xx 10^-7)/15`
= 2 × 10−7 Ω m
Therefore, the resistivity of the material is 2 × 10−7 Ω m.
RELATED QUESTIONS
What conclusion can you draw from the following observations on a resistor made of alloy manganin?
| Current A |
Voltage V |
Current A |
Voltage V |
| 0.2 | 3.94 | 3.0 | 59.2 |
| 0.4 | 7.87 | 4.0 | 78.8 |
| 0.6 | 11.8 | 5.0 | 98.6 |
| 0.8 | 15.7 | 6.0 | 118.5 |
| 1.0 | 19.7 | 7.0 | 138.2 |
| 2.0 | 39.4 | 8.0 | 158.0 |
A heating element is marked 210 V, 630 W. What is the value of the current drawn by the element when connected to a 210 V dc source?
A heating element is marked 210 V, 630 W. Find the resistance of the element when connected to a 210 V dc source.
A wire of length 1 m and radius 0.1 mm has a resistance of 100 Ω. Find the resistivity of the material.
A uniform wire of resistance 100 Ω is melted and recast as a wire whose length is double that of the original. What would be the resistance of the wire?
What length of a copper wire of cross-sectional area 0.01 mm2 will be needed to prepare a resistance of 1 kΩ? Resistivity of copper = 1.7 × 10–8 Ωm
The electrochemical equivalent of a material depends on _______________ .
How does the resistivity of a semiconductor change with rise of temperature ? Explain.
If R1 and R2 are filament resistances of a 200 W and a 100 W bulb respectively, designed to operate on the same voltage, then:
Choose the correct alternative:
The resistivity of the alloy manganin is nearly independent of/increases rapidly with increase of temperature.
Choose the correct alternative:
The resistivity of a typical insulator (e.g., amber) is greater than that of a metal by a factor of the order of (1022/1023).
Fuse wire should have
