1.Units, Dimensions and Measurement
hard

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

$4$

B

$8$

C

$6$

D

$5$

(JEE MAIN-2024)

Solution

$\mathrm{T}=2 \pi \sqrt{\frac{\ell}{\mathrm{g}}}$

$\mathrm{g}=\frac{4 \pi^2 \ell}{\mathrm{T}^2}$

$\frac{\Delta \mathrm{g}}{\mathrm{g}}=\frac{\Delta \ell}{\ell}+\frac{2 \Delta \mathrm{T}}{\mathrm{T}}$

$\quad=\frac{0.2}{20}+2\left(\frac{1}{40}\right)$

$=\frac{0.3}{20}$

$\text { Percentage change }=\frac{0.3}{20} \times 100=6 \%$

Standard 11
Physics

Similar Questions

Start a Free Trial Now

Confusing about what to choose? Our team will schedule a demo shortly.