A student in the laboratory measures thickness of a wire using screw gauge. The readings are $1.22\,mm , 1.23\,mm , 1.19\,mm$ and $1.20\,mm$. The percentage error is $\frac{ x }{121} \%$. The value of $x$ is …………..

An optical bench has $1.5 m$ long scale having four equal divisions in each $cm$. While measuring the focal length of a convex lens, the lens is kept at $75 cm$ mark of the scale and the object pin is kept at $45 cm$ mark. The image of the object pin on the other side of the lens overlaps with image pin that is kept at $135 cm$ mark. In this experiment, the percentage error in the measurement of the focal length of the lens is. . . . .

If $P = \frac{{{A^3}}}{{{B^{5/2}}}}$ and $\Delta A$ is absolute error in $A$ and $\Delta B$ is absolute error in $B$ then absolute error $\Delta P$ in $P$ is

Zero error of an instrument introduces

A student determined Young's Modulus of elasticity using the formula $Y=\frac{M g L^{3}}{4 b d^{3} \delta} .$ The value of $g$ is taken to be $9.8 \,{m} / {s}^{2}$, without any significant error, his observation are as following.

Then the fractional error in the measurement of ${Y}$ is