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JEE Main 202623 JanuaryMorning Shift

Exam: JEE Main
Year: 2026
Date: 23 January
Shift: Morning Shift
Subject: Physics
Chapter: Mathematics in Physics

JEE Main 2026 · 23 January · Morning Shift · Physics · Mathematics in Physics

Four persons measure the length of a rod as 20.00 ~cm, 19.75 ~cm,...

Four persons measure the length of a rod as

20.00 \mathrm{~cm}, 19.75 \mathrm{~cm}, 17.01 \mathrm{~cm}

and 18.25 cm. The relative error in the measurement of average length of the rod is :

Options

A0.08
B0.06
C0.18
D0.24

Correct answer

B. 0.06

Step-by-step solution

Mean

= \frac{20.00+19.75+17.01+18.25}{4} = \frac{75.01}{4} = 18.7525

cm.
Absolute errors:

|20.00-18.7525|=1.2475

,

|19.75-18.7525|=0.9975

,

|17.01-18.7525|=1.7425

,

|18.25-18.7525|=0.5025

.
Mean absolute error

= \frac{1.2475+0.9975+1.7425+0.5025}{4} = \frac{4.49}{4} = 1.1225

.
Relative error

= \frac{1.1225}{18.7525} \approx 0.06

.

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