$A$ set of defective observation weights is used by a student to find the mass of an object using a physical balance. $A$ large number of readings will reduce:

The measured value of the length of a simple pendulum is $20 \ cm$ with $2 \ mm$ accuracy. The time for $50$ oscillations was measured to be $40 \ s$ with $1 \ s$ resolution. From these measurements,the accuracy in the measurement of acceleration due to gravity is $N \%$. The value of $N$ is:

$A$ balance is made using a uniform metre scale of mass $100 \ g$ and two plates each of mass $200 \ g$ fixed at the two ends of the scale. The balance is pivoted at the $45 \ cm$ mark. If a $300 \ g$ weight is placed in the plate at $0 \ cm$ to weigh vegetables placed in the plate at $100 \ cm$, what is the error in the measurement (in $g$)?

What is least count? What is called least count error?

In the expression for time period $T$ of a simple pendulum $T = 2 \pi \sqrt{\frac{l}{g}}$,if the percentage error in time period $T$ and length $l$ are $2 \%$ and $2 \%$ respectively,then the percentage error in acceleration due to gravity $g$ is equal to ......... $\%$

Mass and volume of a body are found to be $(6.00 \pm 0.03) \text{ kg}$ and $(2.00 \pm 0.02) \text{ m}^3$ respectively. Then the density of a body is