JEE Main20206 Sep 2020Evening ShiftPhysicsExperimental PhysicsActual
A student measuring the diameter of a pencil of circular cross-section with the help of a vernier scale records the following four readings 5 . 50 mm , 5 . 55 mm , 5 . 34 mm , 5 . 65 mm . The average of these four reading is 5 . 5375 mm and the standard deviation of the data is 0 . 07395 mm . The average diameter of the pencil should therefore be recorded as :
Options
- A5 .5375 ± 0 .0739 mm
- B5 .5375 ± 0 .0740 mm
- C5 .538 ± 0 .074 mm
- D5 .54 ± 0 .07 mm
Correct answer
D. 5 .54 ± 0 .07 mm
Step-by-step solution
Significant rule says that reading should has same significant figure as that of reading given. 5 . 5375 → rounded to → 5 . 54 . 0.07395 → rounded to → 0.07 therefore, 5 . 54 ± 0 . 07   m m