The period of oscillation of a simple pendulum in the experiment is recorded as $2.63\, s, 2.56 s, 2.42\, s, 2.71\, s$ and $2.80 \,s$ respectively. The average absolute error is ......... $s$

The measured value of the length of a simple pendulum is $20 \mathrm{~cm}$ with $2 \mathrm{~mm}$ accuracy. The time for $50$ oscillations was measured to be $40$ seconds with $1$ second resolution. From these measurements, the accuracy in the measurement of acceleration due to gravity is $\mathrm{N} \%$. The value of $\mathrm{N}$ is:

A student performs an experiment to determine the Young's modulus of a wire, exactly $2 \mathrm{~m}$ long, by Searle's method. In a particular reading, the student measures the extension in the length of the wire to be $0.8 \mathrm{~mm}$ with an uncertainty of $\pm 0.05 \mathrm{~mm}$ at a load of exactly $1.0 \mathrm{~kg}$. The student also measures the diameter of the wire to be $0.4 \mathrm{~mm}$ with an uncertainty of $\pm 0.01 \mathrm{~mm}$. Take $g=9.8 \mathrm{~m} / \mathrm{s}^2$ (exact). The Young's modulus obtained from the reading is

The length, breadth and thickness of a strip are $(10.0 \pm 0.1)\; cm ,(1.00 \pm 0.01) \;cm$ and $(0.100 \pm 0.001)\; cm$ respectively. The most probable error in its volume will be?

If $a, b, c$ are the percentage errors in the measurement of $A, B$ and $C$, then the percentage error in $ABC$ would be approximately

Explain least count and least count error. Write a note on least count error.