Units & measurements practice · Medium

A physicist performs an experiment and takes 200 readings. He repeats the same experiment and now takes 800 readings. By doing so the probable error

State the number of significant figures in the
following:
(i) 2.000 m (ii) 5100 kg (iii) 0.050 cm.

The dimensions of Wien’s constant are

To determine the Young’s modulus of a wire, the formula is $Y = \frac{F}{A} \times \frac{L}{{\Delta L}}$; where L= length, A= area of cross-section of the wire, ${\Delta L}$= change in length of the wire when stretched with a force F. The conversion factor to change it from CGS to MKS system is

The physical quantity that does not have the dimensional formula $\left[\mathrm{ML}^{-1} \mathrm{~T}^{-2}\right]$ is

The unit of Young's modulus is

$\left[\mathrm{Y}=\frac{\text {Stress}}{\text {Strain}}=\frac{\text {force} / \text {area}}{\Delta \ell / \mathrm{L}}\right]$

Young’s modulus of a material has the same units as

Unit of magnetic flux is:

The dimensional formula of intensity of magnetisation is

If the acceleration due to gravity is 10$\;\mathrm{m}{\mathrm{s}^{ - 2}}$ and the units of length and time are changed in kilometer and hour respectively, the numerical value of acceleration is

The velocity of a particle as a function of time is given as $v(t)=a t^2+b t+\frac{c}{t^2+d}$, where $a, b, c$ and $d$ are constants, The dimensions of $\left[\frac{a b}{c d}\right]$ is

The SI unit of universal gas constant (R) is

Assertion A: If in five complete rotations of the circular scale, the distance travelled on main scale of the screw gauge in 5 mm and there are 50 total divisions on circular scale, then least count of screw gauge is 0.002 cm.
Reason R: Least count $=\frac{\text { Pitch }}{\text { Total divisions on circular scale }}$

If the speed of light (c), acceleration due to gravity (g) and pressure (p) are taken as the fundamental quantities, then the dimension of gravitational constant is

The dimension of $a \times b$ in the relation $E = \frac{{b - {x^2}}}{{at}},\,$ where $E$ is the energy, $x$ is the displacement and $t$ is time are

The circular head of screw gauge is divided into 200 division and move 1 mm a head in one revolution. Find the pitch of screw gauge:

Given, Force $= \frac{\alpha }{{\mathrm{density} + \mathrm{\;}{\mathrm{\beta }^3}}}$ What are the dimensions of $\mathrm{\alpha },\mathrm{\beta }?$

The physical quantity which does not have the same dimensions as the other three is

In a slide calliper, $n$ divisions of vernier scale coincides with $(n-1)$ divisions of main scale. The least count of the instrument is

The fundamental unit, which has the same power in the dimensional formulae of surface tension and viscosity is

Assertion: The number of significant figures in 0.100 is 1 .

Reason: The zeros at the end of a number are always meaningless.

Given that the amplitude A of scattered light is :

(i) Directly proportional to the amplitude $\left(A_o\right)$ of incident light.

(ii) Directly proportional to the volume $(V)$ of the scattering particle

(iii) Inversely proportional to the distance (r) from the scattered particle

(iv) Depend upon the wavelength $(\lambda)$ of the scattered light. then:

Which of the following is not a unit of energy

Rounding off the value 324.13821 upto four significant digits is

Dimensional formula for $\frac{h^2 v^2 / m c^2}{1+\frac{h v}{m c^2}}$ is (where $h$ is planck's constant, $v$ is frequency of light, $m$ is mass and $c$ is speed of light).

The physical quantity which has the dimensional formula $\left[ {{\mathrm{M}^1}{\mathrm{T}^{ - 3}}} \right]$ is

Statement-I: Positive zero error is added in measurement.
Statement-II: Defect may occurs during manufacturing of measuring instruments.

Resistance of a given wire is obtained by measuring the current flowing in it and the voltage difference applied across it. If the percentage errors in the measurement of the current and the voltage difference are 3% each, then error in the value of resistance of the wire is

Which of the following measurement is most precise?

Assertion: Mass of a body and the velocity, with which it is moving, cannot be multiplied.

Reason: It is because, mass is a scalar and velocity is a vector quantity. In addition to this, the dimensions of mass and velocity are different.