The $$rms$$ value of the electric field of the light coming from the Sun is $$720$$ $$N/C.$$ The average total energy density of the electromagnetic wave is

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