A student measures the time period of `100` ocillations 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 men time should be:

Options

A. `(92 +-2)s`
B. `(92 +- 5)s`
C. `(92 +- 1.8)s`
D. `(92 +- 3)s`

Answer

(a)

Explanation

Mean value of time period
`=(90 + 91 +92 +95)/(4) = 92 s`
Mean absolute error
`=( | 92 - 90 | + |92- 91| + |92 - 92 | + |92 - 95|)/(4)`
`=( 2+1+0 +3)/(4) = 1.5 s`
:. Value of time period `= (92 +- 1.5)s`
As least count = 1s
:. Value of time period = `(92 +- 2) s.`