Question
Two identical p-ri junctions may be connected in series with a battery in three ways (figure). The potential difference across the two p-n. junctions are equal in:
  1. Circuit 1 and circuit 2.
  2. Circuit 2 and circuit 3.
  3. Circuit 3 and circuit 1.
  4. Circuit 1 only.

Answer

  1. Circuit 2 and circuit 3.

Explanation:

In circuit 1, one diode is forward biassed and the other diode is reverse biassed. The forward-biassed diode offers zero resistance (ideally) to the current flow, so it can be replaced by a short circuit. The voltage drop across the first diode will be zero. The second diode is reverse biassed, so it can be replaced by an open circuit; hence, the voltage drop across this diode will be maximum.

In circuit 2, both the diodes are forward biassed, so they can be replaced by short circuits; hence, the voltage drop across both of them will be minimum and equal.

In circuit 3, both the diodes are reverse biassed, so both can be replaced by open circuits; hence, the voltage drop across both of them will be maximum and equal.

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

Similar questions

In which of the following decays the element does not change?

  1. $\alpha-\text{decay}$

  2. $\beta^+-\text{decay}$

  3. $\beta^--\text{decay}$

  4. $\gamma-\text{decay}$

A projectile is projected with velocity of $25\, m / s$ at an angle $\theta$ with the horizontal. After t seconds its inclination with horizontal becomes zero. If $R$ represents horizontal range of the projectile, the value of $\theta$ will be : [use $g =10 m / s ^{2}$ ]
A sphere, a cube and a thin circular plate, all made of the same mass and finish are heated to a temperature of $200^{\circ} C$. Which of these objects will cool slowest, when left in air at room temperature?
As the temperature of a conductor increases, its resistivity and conductivity change. The ratio of resistivity to conductivity:
  1. Increases.
  2. Decreases.
  3. Remains constant.
  4. May increase or decrease, depending on the actual temperature.
A ball of mass $2\;kg$ and another of mass $4\; kg$ are dropped together from a $60$ feet tall building. After a fall of $30$ feet each towards earth, their respective kinetic energies will be in the ratio of?
Two particles $P$ and $Q$ describe $SHM$ of same amplitude $a$ , frequency $v$ along the same straight line. The maximum distance between the two particles is $a \sqrt 2$ . The initial phase difference between the particles is
A wire suspended vertically from one of its ends is stretched by attaching a weight of $200\, N$ to the lower end. The weight stretches the wire by $1\, mm$ Then the elastic energy stored in the wire is ........ $J$
The Doppler's effect is applicable for
A body dropped from a height $1\,m$ on a floor rises to a height $25\,cm$ after first  rebound. The coefficient of restitution is :-
Two exactly similar wires of steel and copper are stretched by equal forces. If the difference in their elongations is $0.5$ cm, the elongation $(l)$ of each wire is ${Y_s}({\rm{steel}}) = 2.0 \times {10^{11}}\,N/{m^2}$${Y_c}({\rm{copper}}) = 1.2 \times {10^{11}}\,N/{m^2}$