Tag: dynamics - explaining motion

Quizzes (15) Questions (91)

Questions Related to dynamics - explaining motion

Multiple choice physics dynamics - explaining motion system of unit summary of si units system of units

If 1 g cm$^{-3} = 10^3\,kg\, m^{-3}$ then $10^6kgm^{-3}=$

  1. $10^{-3}\,g\,cm^{-3}$
  2. $10^{6}\,g\,cm^{-3}$
  3. $10^{3}\,g\,cm^{-3}$
  4. $10^{-6}\,g\,cm^{-3}$
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation

Given, $1 g cm^{-3}=10^3 kgm^{-3}$

If we multiply $10^3$ on both sides, $10^3 g cm^{-3}=10^3\times 10^3 kgm^{-3}$
or $10^3 g cm^{-3}=10^6 kgm^{-3}$
Thus, option C will be the right option. 

Multiple choice physics dynamics - explaining motion system of unit summary of si units system of units

SI unit of Magnetic flux is weber and its CGS unit is maxwell. Then 1 Wb = :

  1. $10^6$ maxwell
  2. $10^7$ maxwell
  3. $10^8$ maxwell
  4. $10^9$ maxwell
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation

Magnetic flux is the product of magnetic field and area.

As SI unit of magnetic flux is weber, so $1 \, Wb=Tesla (T)\times m^2$
where $1 \, T=10^{4} \, gauss$ and $1 m^2=10^4 cm^2$
(T and gauss is the SI and CGS unit of magnetic field )
So, $1 \, Wb=10^4 \, gauss \times 10^4cm^2=10^8 $ maxwell

Multiple choice physics dynamics - explaining motion system of unit summary of si units system of units

$S = A(1 - e^{-Bxt})$, where S is speed and x is displacement. The unit of B is :

  1. $m^{-1}s^{-1}$
  2. $m^{-2}s$
  3. $s^{-2}$
  4. $s^{-1}$
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

It is given that $x$ is displacement and $t$ is time.
Unit of $x$ is $m$ and that of time t is $s$.
Since, the quantity $Bxt$ must be dimensionless.
$\implies$ Unit of B must be $m^{-1}s^{-1}$.

Multiple choice physics dynamics - explaining motion exponentiation index notation and products of prime factors powers

Arrange the following lengths in the increasing order of their magnitudes :
1 meter, 1 centimeter, 1 kilometer, 1 millimeter .

  1. 1 meter < 1 centimeter < 1 kilometer < 1 millimeter

  2. 1 millimeter < 1 meter < 1 centimeter < 1 kilometer

  3. 1 millimeter < 1 centimeter < 1 meter < 1 kilometer

  4. none of these
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation

1 kilometer = 10$^3$ meter

1 centimeter = 10$^{-2}$ meter
1 millimeter = 10$^{-3}$ meter

Ascending order of length :
1 millimeter < 1 centimeter < 1meter < 1 kilometer

Multiple choice physics dynamics - explaining motion exponentiation index notation and products of prime factors powers

The wrong unit conversion among the following is

  1. 1 angstrom = $10^{-10} m$
  2. 1 fermi = $10^{-15}$ m
  3. 1 light year = $9.46 \times 10^{15} m$
  4. 1 astronomical unit = $1.496 \times 10^{-11} m$
Reveal answer Fill a bubble to check yourself
D Correct answer
Explanation
$A)1 $Angstrom: $1$ Ångström is equal to$ 0.1 $nanometers. Expressed in the SI base unit meters $1$ Ångström is equal to $1 \times 10^{-10}$ meters. $1 Å = 0.0000000001 m.$

$B)$Definition of fermi unit: $≡ 1\times 10^{−15} m.$

$C)$The light-year is a unit of length used to express astronomical distances and measures about $9.46$ trillion kilometres $(9.46 \times 10^{12} km)$ or $5.88$ trillion miles $(5.88 \times 10^{12} mi).$

$D)$The total radiation power received from the sun on a unit area perpendicular to the sun rays at the mean earth-sun distance, termed an astronomical unit, is called the solar constant (SC), where $1$ astronomical unit $= 1 AU = 1.496 \times 10^{11} m.$

So $D$ is wrong unit conversion