Share

Books Shortlist

# Solution for If There is an Error of 2% in Measuring the Length of a Simple Pendulum, Then Percentage Error in Its Period is (A)1% (B) 2% (C) 3% (D) 4% - CBSE (Science) Class 12 - Mathematics

#### Question

If there is an error of 2% in measuring the length of a simple pendulum, then percentage error in its period is
(a)1%
(b) 2%
(c) 3%
(d) 4%

#### Solution

(a) 1%
Let l be the length if the pendulum and T be the period.

$\text { Also, let ∆ l be the error in the length and ∆ T be the error in the period } .$

$\text { We have }$

$\frac{∆ l}{l} \times 100 = 2$

$\Rightarrow \frac{dl}{l} \times 100 = 2$

$\text { Now,} T = 2\pi\sqrt{\frac{l}{g}}$

$\text { Taking \log on both sides, we get }$

$\log T = \log 2\pi + \frac{1}{2}\log l - \frac{1}{2}\log g$

$\text { Differentiating both sides w . r . t . x, we get }$

$\frac{1}{T}\frac{dT}{dl} = \frac{1}{2l}$

$\Rightarrow \frac{dT}{dl} = \frac{T}{2l}$

$\Rightarrow \frac{dl}{l} \times 100 = 2\frac{dT}{T} \times 100$

$\Rightarrow \frac{dT}{T} \times 100 = \frac{2}{2}$

$\Rightarrow \frac{∆ T}{T} \times 100 = 1$

$\text { Hence, there is an error of 1 % in calculating the period of the pendulum } .$

Is there an error in this question or solution?

#### Video TutorialsVIEW ALL [2]

Solution If There is an Error of 2% in Measuring the Length of a Simple Pendulum, Then Percentage Error in Its Period is (A)1% (B) 2% (C) 3% (D) 4% Concept: Approximations.
S