RRB Technician Grade 3 previous year question
A wire has a resistance of 10 Ω. If it is stretched to three times its original length (volume remaining constant), its new resistance will be ________.
Asked in RRB Technician Grade 3 (10 Mar 2026 Shift 1) · Science
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Correct answer: (A) 90 Ω
Since volume is constant, stretching the wire to 3 times its length reduces its cross-sectional area to 1/3. As R ∝ L/A, the new resistance is R×(3)×(3) = R×9 = 10×9 = 90 Ω.
हिंदी में प्रश्न
किसी तार का प्रतिरोध 10 Ω है। यदि इसे अपनी मूल लंबाई (आयतन स्थिर रहते हुए) की तीन गुना तक बढ़ाया जाता है, तो इसका नया प्रतिरोध ________ होगा।
उत्तर जाँचने के लिए किसी विकल्प पर टैप करें।
उत्तर और व्याख्या देखें
सही उत्तर: (A) 90 Ω
आयतन स्थिर रहने के कारण, तार को 3 गुना लंबा करने पर उसका अनुप्रस्थ काट क्षेत्रफल 1/3 रह जाता है। चूंकि R ∝ L/A है, नया प्रतिरोध = R×9 = 10×9 = 90 ओम होगा।
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