It's a quirk of units: notice that the conversion between them is dimensionful, and has the value $3\times 10^8\,\mathrm{m/s}$, which is the speed of light.
In the CGS system both fields have the same units, and field-squared is an energy density.

In SI units, the energy density for a configuration of fields is given by 
\begin{align}
\frac{dU}{dV} &amp;= \frac12\left( \epsilon_0 E^2 + \frac1{\mu_0} B^2 \right)\\
&amp;= \frac{\epsilon_0}2 \left( E^2 + c^2 B^2 \right)
\end{align}
which tells you that, given the field strength ratio $c$ you have calculated for electromagnetic waves, the energy of an EM wave is shared equally between its electric and magnetic components.

We do tend to usually think about the interaction between EM waves and materials in terms of the electric field component, but that's a bias because it's relatively easy to liberate free electric charges, and magnetic interactions only occur at second order. Spend some time around folks thinking about plasma physics, or wrap your head around the behavior of the sun's magnetic field reversal cycle, for a very different perspective.

Why are magnetic fields so much weaker than electric?
usually i help people with whatever they need, this time i'm asking for your help.

i'm trying to get a specific row from my database after preforming multiple checkbox select  i spend 50 hours on that and i couldn't manage to do that.
each time i'm changing something in my code i get a different ERROR.
i was looking for an answer in every HTML page that exist on the INTERNET !

please show me the light..

here is a part of my form.... value means "size" of the toy



    &lt;div class=""&gt;&lt;input type="checkbox" name="toys[]" value="6X2" /&gt;&lt;label&gt;&lt;/label&gt;&lt;/div&gt;
    &lt;div class=""&gt;&lt;input type="checkbox" name="toys[]" value="4X3" /&gt;&lt;label&gt;&lt;/label&gt;&lt;/div&gt;
    &lt;div class=""&gt;&lt;input type="checkbox" name="toys[]" value="8X2.5" /&gt;&lt;label&gt;&lt;/label&gt;&lt;/div&gt;&lt;/strike&gt;


here is the PHP code...

  if (isset($_POST['toys'])) {

     foreach($_POST['toys'] as $each_check) {

      }
  }

  $query = $db-&gt;query = 'SELECT * FROM `toys` WHERE SIZE = '.$each_check;   


echo "&lt;table&gt;";
    echo "&lt;tr&gt;
            &lt;th&gt;ratio&lt;/th&gt;
            &lt;th&gt;size&lt;/th&gt;
            &lt;th&gt;built&lt;/th&gt;
            &lt;th&gt;description&lt;/th&gt;            
          &lt;/tr&gt;";



while ($row = $query-&gt;fetch(PDO::FETCH_ASSOC)) 

        echo "&lt;tr&gt;&lt;td&gt;" . $row['ratio'] .
            "&lt;/td&gt;&lt;td&gt;" . $row['size'] .
            "&lt;/td&gt;&lt;td&gt;" . $row['built'] .
            "&lt;/td&gt;&lt;td&gt;" . $row['description'] .
            "&lt;/td&gt;&lt;/tr&gt;";
echo "&lt;/table&gt;";        

