Question

The least count of a stop watch is 0.2 second. The time of 20 oscillations of a pendulum is measured to be 25 second. The percentage error in the measurement of time will be(a) 8%(b) 1.8%(c) 0.8%(d) 0.1%

Answer 1

Answer:

The percentage error in the measurement of time is 0.8 %.

(c) is correct option.

Explanation:

Given that,

Least count of stop watch= 0.2 sec

Number of oscillation = 20

Time = 25 sec

We need to calculate the time period

Using formula of time

$T=\dfrac{t}{n}$

We need to calculate the percentage error in the measurement of time

Using formula of percentage error

$Percentage\ error=\dfrac{\Delta T}{T}\times100$

$\dfrac{\Delta T}{T}=\dfrac{\Delta t}{t}$

$Percentage\ error=\dfrac{\Delta t}{t}\times100$

$Percentage\ error=\dfrac{0.2}{25}\times100$

$Percentage\ error=0.8\%$

Hence, The percentage error in the measurement of time is 0.8 %.

Answer 2

0.8%.................