JEE Main 2024 (Online) 1st February Morning Shift | Units & Measurements Question 21 | Physics

The radius $(\mathrm{r})$, length $(l)$ and resistance $(\mathrm{R})$ of a metal wire was measured in the laboratory as

$$ \begin{aligned} & \mathrm{r}=(0.35 \pm 0.05) ~\mathrm{cm} \\\\ & \mathrm{R}=(100 \pm 10) ~\mathrm{ohm} \\\\ & l=(15 \pm 0.2)~ \mathrm{cm} \end{aligned} $$

The percentage error in resistivity of the material of the wire is :

$37.3 \%$

$25.6 \%$

$35.6 \%$

$39.9 \%$

JEE Main 2024 (Online) 31st January Evening Shift

MCQ (Single Correct Answer)

-1

Consider two physical quantities $$A$$ and $$B$$ related to each other as $$E=\frac{B-x^2}{A t}$$ where $$E, x$$ and $$t$$ have dimensions of energy, length and time respectively. The dimension of $$A B$$ is

$$L^{-2} M^1 T^0$$

$$L^2 M^{-1} T^1$$

$$L^0 M^{-1} T^1$$

$$L^{-2} M^{-1} T^1$$

JEE Main 2024 (Online) 31st January Evening Shift

MCQ (Single Correct Answer)

-1

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: