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Magnetic Field — Physics STD 11 Science — Question

Gujarat BoardEnglish MediumSTD 11 SciencePhysicsMagnetic Field1 Mark
MCQ
Let $\overrightarrow{\text{E}}$ and $\overrightarrow{\text{B}}$ denote electric and magnetic fields in a frame $S$ and $\overrightarrow{\text{E}}$ and $\overrightarrow{\text{B}}$ in another frame $S$ moving with respect to $S$ at a velocity $\overrightarrow{\text{v}}.$ Two of the following equations are wrong. Identify them.
  1. $\text{B}_\text{y},=\text{B}_\text{y}+\frac{\text{vE}_\text{z}}{\text{c}^2}$
  2. $\text{E}_\text{y},=\text{E}_\text{y}+\frac{\text{vB}_\text{z}}{\text{c}^2}$
  3. $\text{B}'_\text{y}=\text{B}_\text{y}+\text{v}\text{E}_\text{z}$
  4. $\text{E}'_\text{y}=\text{E}_\text{y}+\text{vB}_\text{z}$
  • A
    only $A$
  • B
    $A$ and $B$
  • ✓
    $B$ and $C$
  • D
    None of these
✓

Answer

Correct option: C.
$B$ and $C$
$\text{qE}=\text{qvB}$
$\Rightarrow\text{e}=\text{vB}$ By dimensionally $b\ \&$ care wrong
$\Rightarrow\text{v}\text{E}=\text{v}^2\text{B}$
$\Rightarrow\text{B}=\frac{\text{vE}}{\text{v} ^2}$

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