Download App

Semiconductor Electronic: Material, Devices And Simple Circuits — Physics STD 12 Science — Question

Gujarat BoardEnglish MediumSTD 12 SciencePhysicsSemiconductor Electronic: Material, Devices And Simple Circuits1 Mark
MCQ
For detecting the light $.........$
  • A
    The photodiode has to be forward biased.
  • ✓
    The photodiode has to be reversed biased.
  • C
    The $\text{LED}$ has to connected in forward bias mode.
  • D
    The $\text{LED}$ has to be connected in reverse bias mode.
✓

Answer

Correct option: B.
The photodiode has to be reversed biased.
Photo diode is used to detect light.
In reverse biased condition, the width of depletion region increases as the the applied reverse bias voltage increases across the diode. So, by applying a larger voltage, more of the incident photons are converted to electric current thereby increasing the efficiency.
In forward biased condition, the width of depletion region decreases so only a small portion of the incident photons get converted to electric current and hence the efficiency is less.
Hence photo diode in reverse biased condition detects light.

Need a full question paper?

Generate a complete, print-ready paper with questions like this in minutes — across 16+ boards, with answer keys.

Start Generating Free

Explore more

More "M.C.Q (1 Marks)" from Semiconductor Electronic: Material, Devices And Simple Circuits→Semiconductor Electronic: Material, Devices And Simple Circuits — all question types→Physics STD 12 Science question papers→Gujarat Board STD 12 Science question papers→Gujarat Board question paper generator→

Similar questions

A battery of internal resistance one ohm and $emf$ $3\,volt$ sends a current through $1\,metre$ of uniform wire of resistance $5\,\Omega $. The pole of the cell of $emf$ $1.4\,volt$ are connected to two points on the wire so that no current passes through this cell. Then, the potential gradient of the wire is
→
An infinitely long cylinder is kept parallel to an uniform magnetic field $B$ directed along positive $z$ axis. The direction of induced current as seen from the $z$ axis will be
→
In an $LRC$ series circuit at resonance current in the circuit is $10\sqrt 2\  A$. If now frequency of the source is changed such that now current lags by $45^o$ than applied voltage in the circuit , which of the following is correct
→
In a parallel beam of white light is incident on a converging lens, the colour which is brought to focus nearest to the lens is
→
In the ideal double-slit experiment , when a glass-plate (refractive index $1.5$ ) of thickness $t$ is introduced in the path of one of the interfering beams (wave-length $\lambda$ ), the intensity at the position where the central maximum occurred previously remains unchanged. The minimum thickness of the glass-plate is
→
A $280$ ohm electric bulb is connected to $200V$ electric line. The peak value of current in the bulb will be
→
A metallic surface with work function of $2 \,eV$, on heating to a temperature of $800 \,K$ gives an emission current of $1 \,mA$. If another metallic surface having the same surface area, same emission constant but work function $4\, eV$ is heated to a temperature of $1600\, K$, then the emission current will be......$mA$
→
What is the range of the characteristic impedance of a coaxial cable?
→
The maximum peak to peak voltage of an $AM$ wire is $24 \,mV$ and the minimum peak to peak voltage is $8\, mV$. The modulation factor is.....$\%$
→
The threshold wavelength for photoelectric effect of a metal is 6500 Å. The work function of the metal is approximately
→