The circuit has two oppositively connected ideal diodes in parallel. What is the current following in the circuit?

In the following, which one of the diodes is reverse biased?

The anode voltage of a photocell is kept fixed. The wavelength $$\lambda $$ of the light falling on the cathode is gradually changed. The plate current $${\rm I}$$ of the photocell varies as follows

If the lattice constant of this semiconductor is decreased, then which of the following is correct?