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

The energy spectrum of $$\beta $$-particles [ number $$N(E)$$ as a function of $$\beta $$-energy $$E$$ ] emitted from a radioactive source is

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