Four silicon diodes are connected as shown in the figure. Assuming the diodes to be ideal, the current through the resistor R is 

The diodes are said to be ideal means it has negligible resistance.
$\therefore$ Total Resistance (R)  $=50\Omega$
    Potential difference, V= 5V
$\therefore$ current through resistance,  $I=\frac{V}{R}=\frac{5}{50}=0.1A$