JEE PHYSICS MCQ: UNITS & MEASUREMENTS

1 Medium

1 of 1

Application +4 | -1

A screw gauge of pitch

0.5 \mathrm{~mm}

is used to measure the diameter of uniform wire of length

6.8 \mathrm{~cm}

, the main scale reading is

1.5 \mathrm{~mm}

and circular scale reading is 7 . The calculated curved surface area of wire to appropriate significant figures is :
[Screw gauge has 50 divisions on its circular scale]

View answer and explanation

Correct option: B

3.4 \mathrm{~cm}^2

Option B (

3.4 \mathrm{~cm}^2

) is correct because it calculates the diameter using the screw gauge readings and then calculates the curved surface area of the wire.

More Questions from UNITS & MEASUREMENTS

Practice All Chapter MCQs →

Assertion :

\sqrt{\frac{\text { Modulus of elasticity }}{\text { Density }}}

has the unit

\mathrm{ms}^{-1} \text {. }

Reason: Acceleration has the dimensions of

\frac{1}{\left(\sqrt{\varepsilon_0 \mu_0}\right) t} \text {. }

The method of dimensional analysis can be used to derive which of the following relations? Statement-I: Dimensions of constant of proportionality of constants can be derived from dimensional method
Statement-II: Numerical value of constant of proportionality can be found from experiments only The dimensions of torque are The physical quantity having the dimensions

\left[ {{\mathrm{M}^{ - 1}}{\mathrm{L}^{ - 3}}{\mathrm{A}^2}{T^3}} \right]

is A quantity X is given by

{\varepsilon _0}L\frac{{\Delta V}}{{\Delta t}},\;

, where

{\varepsilon _0}

is the permittivity of free space, L is a length,

{\Delta V}

is a potential difference and

{\Delta t}

is a time interval. The dimensional formula for X is the same as that of