Tag: need of unit for measurement

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Multiple choice standardized measurement measurement of physical quantities need of unit for measurement measurements and experimentation physics

The dimensions of the quantities in one (or more) of the following pairs are the same. Identify the pair(s).

  1. Torque and work

  2. Angular momentum and work

  3. Energy and Young's modulus

  4. Light year and wavelength
Reveal answer Fill a bubble to check yourself
A,D Correct answer
Explanation

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

Work$={ M }^{ 1 }{ L }^{ 2 }{ T }^{ -2 }$
angular momentum(L)=${ M }^{ 1 }{ L }^{ 2 }{ T }^{ -1 }$
Energy$={ M }^{ 1 }{ L }^{ 2 }{ T }^{ -2 }$
Young's Modulus $(Y)$$={ M }^{ 1 }{ L }^{ 2 }{ T }^{ -2 }$
Light year$=L$
Wavelength$=L$

Multiple choice standardized measurement measurement of physical quantities need of unit for measurement measurements and experimentation physics

As compared to cumulative average-time learning model, learning model which predicts more cumulative total time to produce more units is known as ____________.

  1. incremental unit time learning model

  2. incremental price learning model

  3. incremental unit average model

  4. incremental cost learning model
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

The incremental unit time learning model assumes that the time required to produce each additional unit decreases as experience is gained, leading to a specific cumulative time prediction.

Multiple choice standardized measurement measurement of physical quantities need of unit for measurement measurements and experimentation physics

The wavelength of light is expressed in

  1. Metre

  2. Micron

  3. Light year

  4. Angstrom
Reveal answer Fill a bubble to check yourself
D Correct answer
Explanation

Angstrom $(\dot A)$ unit of length used chiefly in measuring wavelengths of light, equal to $10^{-10}$ metre, or $0.1$ nanometer.  It is used to express wavelengths of visible light, ultraviolet (UV) light, X rays, and gamma rays.

Multiple choice standardized measurement measurement of physical quantities need of unit for measurement measurements and experimentation physics

If the displacement, velocity and acceleration of a particle at time t be x, v and f respectively, then which one is true?

  1. $f=v^3\dfrac{d^2t}{dx^2}$
  2. $f=-v^3\dfrac{d^2t}{dx^2}$
  3. $f=v^2\dfrac{d^2t}{dx^2}$
  4. $f=-v^2\dfrac{d^2t}{dx^2}$
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

We know that the velocity can be written as:
$v=\dfrac{dx}{dt}$

Therefore, $\dfrac1v=\dfrac{dt}{dx}$

Now, expressing $f$ in terms of velocity.

$\dfrac{d^2t}{dx^2}=\dfrac{d\begin{pmatrix}\dfrac{dt}{dx}\end{pmatrix}}{dx}=\dfrac{d\begin{pmatrix}\frac{1}{v}\end{pmatrix}}{dx}=-\dfrac{1}{v^2}\dfrac{dv}{dt}\times\dfrac{1}{v}$
$\Rightarrow\;f=-v^3\dfrac{d^2t}{dx^2}$