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Q1.7: NCERT Physics - Part 1 UNITS AND MEASUREMENT 1.7 Solution: A student measures the thickness of a human hair by looking at…

⚠️ Common Exam Traps & Conceptual Pitfalls

Students frequently multiply the measured image width by the magnification, producing a value 100 times too large; remember that magnification is the ratio of image size to object size, so the true thickness = observed size ÷ magnification, and keep the units consistent when converting to metres.

A student measures the thickness of a human hair by looking at it through a microscope of magnification 100. He makes 20 observations and finds that the average width of the hair in the field of view of the microscope is 3.5 mm. What is the estimate on the thickness of hair?

Step-by-Step Verified Solution

**Answer:** 0.035 mm=3.5×10−5 m0.035 \text{ mm} = 3.5 \times 10^{-5} \text{ m}. **Step-by-Step Explanation:** Thickness = observed widthmagnification=3.5100=0.035 mm=3.5×10−5 m\frac{\text{observed width}}{\text{magnification}} = \frac{3.5}{100} = 0.035 \text{ mm} = 3.5 \times 10^{-5} \text{ m}.

All Questions in this Chapter

Q1.1 Q1.2 Q1.3 Q1.4 Q1.5 Q1.6 Q1.7 Q1.8 Q1.9 Q1.10 Q1.11 Q1.12 Q1.13 Q1.14 Q1.15 Q1.16 Q1.17

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