Tag: magnetic flux density

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Questions Related to magnetic flux density

Multiple choice physics magnetic fields and electromagnetism magnetic flux density magnetic flux electromagnetic induction

Magnetic field intensity at the centre of coil of 50 turns, radius 0.5 m and carrying a current of 2 A is 

  1. $0.5 \times 10^{-5}T$
  2. $3 \times 10^{-5}T$
  3. $1.25 \times 10^{-4}T$
  4. $4 \times 10^{-5}T$
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation

B = (mu0 * N * I) / (2 * R) = (4 * pi * 10^-7 * 50 * 2) / (2 * 0.5) = (4 * pi * 10^-7 * 100) / 1 = 4 * pi * 10^-5 = 1.256 * 10^-4 T.

Multiple choice physics magnetic fields and electromagnetism magnetic flux density magnetic flux electromagnetic induction

Select the incorrect option

  1. Luminous flux and radiant flux have same dimensions

  2. Luminous flux and luminous intensity have same dimensions

  3. Radiant flux and power have same dimension

  4. Relative luminosity is a dimensionless quantity
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

Luminous flux ( Luminous power) is the amount of perceived power of light. It is measure energy.

Radiant flux (Radiant power) is the amount of radiated power.
While luminous intensity is ratio of luminous flux to solid angle.

Multiple choice physics magnetic fields and electromagnetism magnetic flux density magnetic flux electromagnetic induction

The dimensional formula of magnetic flux is ___________.

  1. $\left[ M{ L }^{ 2 }{ T }^{ -2 }{ A }^{ -1 } \right] $
  2. $\left[ M{ L }^{ 2 }{ T }^{ -3 }{ A }^{ -1 } \right] $
  3. $\left[ { M }^{ -1 }{ L }^{ -2 }{ T }^{ 2 }{ A }^{ 1 } \right] $
  4. $\left[ M{ L }^{ 3 }{ T }^{ -2 }{ A }^{ -1 } \right] $
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

Dimensions of ${ \phi  } _{ B }=$ Unit of $B\times $ Unit of $A$
$=\dfrac { newton }{ ampere-metre } \times { metre }^{ 2 }=\dfrac { newton\times metre }{ ampere } $
$=\dfrac { kg{ ms }^{ -2 }\times m }{ A } =kg{ m }^{ 2 }{ s }^{ -2 }{ A }^{ -1 }=\left[ M{ L }^{ 2 }{ T }^{ -2 }{ A }^{ -1 } \right] $

Multiple choice physics magnetic fields and electromagnetism magnetic flux density magnetic flux electromagnetic induction

In an experiment to measure the velocity of electrons, an electric field $(E)$ and a magnetic field $(B)$ are employed to produce zero deflection. Then :

  1. The two fields are parallel and the velocity is given by $BE$
  2. The two fields are perpendicular and the velocity is given by $E/B$
  3. The two fields are parallel and the velocity is given by $E/B$
  4. The two fields are perpendicular and the velocity is given by $BE$
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

The electric force on electron of charge ${e}$  is,
             $  F= {e}E $ 
                    where, E = electric field.

And Magnetic force ,
            $ F= {e}$ $(V\times B)$
               where, V= velocity of electron in magnetic field
                            B= magnetic field

From the above equations,

          $E= V\times B$
Electric field E is perpendicular to both velocity of electron and the magnetic field. So,  The two field is perpendicular to each other and the velocity of electron is $\dfrac{E}{B}$.

B. The two fields are perpendicular and the velocity is given by $\dfrac{E}{B}$.

Multiple choice physics magnetic fields and electromagnetism magnetic flux density magnetic flux electromagnetic induction

Write the dimensions of Magnetic flux in terms of mass, time, length and charge.

  1. $[M^1L^2T^{-1}Q^{-2}]$
  2. $[M^1L^2T^{-1}Q^{-1}]$
  3. $[M^1L^3T^{-1}Q^{-1}]$
  4. $[M^4L^2T^{-1}Q^{-1}]$
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

B. $[M^1 L^2 T^ {-1}Q^{-1}]$


Dimension of magnetic field, 


$[B]=[M^1L^0Q^{-1}]$ 

Dimension of surface Area,

 $[A]=[L^2]$

The magnetic flux , 

$\phi=B.A$

The dimension of magnetic flux in term of mass, time, length and charge,
$[\phi]= [M^1L^2T^{-1}Q^{-1}]$