Question

Current in the circuit will be:

Answer 1

Hint: In diode circuit system, the current will be passed through forward biased diode and the current will not be passed through the reverse biased diode. So, using this concept we will solve this problem.

Complete answer:
The current will be passed through forward biased diodes and current will not flow from reverse biased diodes. The equivalent circuit as follow:

In this circuit we can see that the reverse diode is removed or neglected in the above circuit as no current is being passed in this circuit.
To obtain the current we need to find total (equivalent) resistance, ${R_{eq}} = $Sum of all resistances in the circuits.
$ {R_{eq}} = 20\Omega + 30\Omega \\
  {R_{eq}} = 50\Omega \\ $
Potential difference, $V = 5V$
Potential difference, $V = I{R_{eq}}$
$I = \dfrac{V}{{{R_{eq}}}}$
All data required in this formula is provided above. So, substituting these values in the above formula we get:
$ I = \dfrac{5}{{50}}A \\
  I = \dfrac{1}{{10}}A \\ $
The current in the above circuit is $\dfrac{1}{{10}}A$.

Note: We saw that a forward biased diode allows current to flow while reverse diode doesn’t but there is a kind of diode which allows current to flow either in forward direction or in reverse direction. This diode is known as Zener diode. This diode is especially designed to pass the current in the reverse direction when certain voltage is reached. It is a highly doped p-n junction.
Uses of Zener diode:
For voltage regulation
As switch
Clippers circuit
Surge suppressors