If the error in measuring the diameter of a circle is $4\%$,the error in the radius of the circle would be (in $\%$)

$A$ simple pendulum is being used to determine the value of gravitational acceleration $g$ at a certain place. The length of the pendulum is $25.0 \; cm$ and a stopwatch with $1 \; s$ resolution measures the time taken for $40$ oscillations to be $50 \; s$. The accuracy in $g$ is ....... $\%$ (in $.40$)

The least count of a stopwatch is $0.2\, s$. The time for $20\, oscillations$ of a pendulum is measured to be $25\, s$. The percentage error in the measurement of time will be ........ $\%$

Explain Absolute Error,Relative Error,and Percentage Error.

An experiment measures quantities $a, b$ and $c$,and quantity $X$ is calculated from $X = ab^2 / c^3$. If the percentage errors in $a, b$ and $c$ are $\pm 1\%, \pm 3\%$ and $\pm 2\%$,respectively,then the percentage error in $X$ will be

$A$ student measures the time period of $100$ oscillations of a simple pendulum four times. The data set is $90\;s$,$91\;s$,$95\;s$,and $92\;s$. If the minimum division in the measuring clock is $1\;s$,then the reported mean time should be