Q. A wire has a resistance of 12 Ω and is made of a material with a resistivity of 3 x 10^-6 Ω·m. If the length of the wire is 4 m, what is its cross-sectional area?
Q. A wire made of material A has a resistivity of 1.5 x 10^-8 Ω·m, while material B has a resistivity of 3.0 x 10^-8 Ω·m. If both wires have the same dimensions, which wire will have a higher resistance?
A.
Wire A
B.
Wire B
C.
Both have the same resistance
D.
Cannot be determined
Solution
Resistance is directly proportional to resistivity; hence, wire B with higher resistivity will have higher resistance.
Q. A wire made of material A has twice the length and half the cross-sectional area of a wire made of material B. If the resistivity of A is ρ, what is the resistance of wire A in terms of the resistance of wire B?
A.
2R
B.
4R
C.
R/2
D.
R/4
Solution
Resistance R = ρ(L/A). For wire A, R_A = ρ(2L/(A/2)) = 4ρ(L/A) = 4R_B.
Understanding resistivity is crucial for students preparing for school and competitive exams in India. This fundamental concept in physics not only helps in grasping the behavior of materials but also plays a significant role in various objective questions and MCQs. Practicing resistivity MCQ questions can enhance your exam preparation and boost your confidence in tackling important questions effectively.
What You Will Practise Here
Definition and significance of resistivity in materials
Key formulas related to resistivity and conductivity
Factors affecting resistivity and their implications
Applications of resistivity in real-world scenarios
Diagrams illustrating resistivity concepts
Comparison of resistivity in different materials
Sample objective questions with detailed explanations
Exam Relevance
The topic of resistivity is frequently featured in CBSE, State Boards, NEET, and JEE exams. Students can expect questions that require them to apply formulas, analyze graphs, or solve numerical problems related to resistivity. Common question patterns include direct MCQs, assertion-reason type questions, and numerical problems that assess conceptual understanding.
Common Mistakes Students Make
Confusing resistivity with resistance and conductivity
Overlooking the temperature dependence of resistivity
Misapplying formulas in numerical problems
Ignoring the significance of units in calculations
Failing to interpret graphical data related to resistivity
FAQs
Question: What is resistivity? Answer: Resistivity is a property of materials that quantifies how strongly they oppose the flow of electric current, typically measured in ohm-meters.
Question: How does temperature affect resistivity? Answer: Generally, the resistivity of conductors increases with temperature, while that of semiconductors decreases.
Question: Why is it important to practice resistivity MCQs? Answer: Practicing resistivity MCQs helps solidify your understanding of the concept and prepares you for various question formats in exams.
Now is the time to enhance your understanding of resistivity! Dive into our practice MCQs and test your knowledge to excel in your exams.
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