Special Purpose Diodes — Prelims Questions

A Zener diode is used for voltage regulation. If the input voltage to the regulator circuit varies from $10,\text{V}$ to $15,\text{V}$ and the Zener voltage is $V_Z = 6.8,\text{V}$, what is the approximate voltage across the load resistor connected in parallel with the Zener diode?

Which of the following statements is INCORRECT regarding a Light Emitting Diode (LED)?

A photodiode is typically operated in reverse bias. What is the primary reason for this operating condition?

A solar cell has an open-circuit voltage ($V_{oc}$) of $0.6,\text{V}$ and a short-circuit current ($I_{sc}$) of $2,\text{A}$. If its fill factor is $0.75$, what is the maximum power ($P_{max}$) that can be obtained from this solar cell?

Which of the following special purpose diodes is primarily used for converting electrical energy into light energy?

An LED emits green light with a wavelength of $550,\text{nm}$. What is the approximate band gap energy of the semiconductor material used in this LED? (Given: Planck's constant $h = 6.626 \times 10^{-34},\text{J}cdot\text{s}$, speed of light $c = 3 \times 10^8,\text{m/s}$, $1,\text{eV} = 1.602 \times 10^{-19},\text{J}$)