MCQ
The drift current in a p-ri junction is:
  • A
    From the n-side to the p-side.
  • B
    From the p-side to the n-side.
  • C
    From the n-side to the p-side if the junction is forward-biased and in the opposite direction if it is reverse-biased.
  • D
    From the p-side to the n-side if the junction is forward-biased and in the opposite direction if it is reverse-biased.

Answer

  1. From the n-side to the p-side.

Explanation:

After the diffusion of majority charge carriers across a p‒n junction, an electric field is set up because of the accumulation of immobile ions at the junction. These further oppose the motion of majority charge carriers across the junction. As a result, electrons from the p region start moving to the n region and holes from the n region start moving to the p region. This constitutes the drift current. As the direction of the current is opposite to the direction of the motion of the electrons, the direction of the drift current is from the n side to the p side.

In forward biasing, there is no movement of electrons from the p region to the n region and of holes from the n region to the p region. Hence, there is not drift current.

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

A non-conducting solid sphere of radius R is uniformly charged. The magnitude of the electric field due to the sphere at a distance r  from its centre

(a) Increases as r increases for r < R

(b) Decreases as r  increases for 0 < r <

(c) Decreases as r  increases for R < r <

(d) a, c

To increase both the resolving power and magnifying power of a telescope:

Assertion  :   A domestic electrical appliance, working on a three pin will continue working even if the top pin is removed.

Reason     : The third pin is used only as a safety device.

(a) If both assertion and reason are true and the reason is the correct explanation of the assertion.

(b) If both assertion and reason are true but reason is not the correct explanation of the assertion.

(c) If assertion is true but reason is false.

(d) If the assertion and reason both are false.

When is the angle of dip at a place equal to 45o?

The cold junction of a thermocouple is maintained at 10. No thermo e.m.f. is developed when the hot junction is maintained at 530 . The neutral temperature is

(a) 260

(b) 270

(c) 265

(d) 520

Which of the following statements related to static electricity is not true?
A particle moves on the X-axis according to the equation $\text{x = A + B}\sin\omega\text{t}.$ The motion is simple harmonic with amplitude:
  1. A
  2. B
  3. A + B
  4. $\sqrt{\text{A}^2+\text{B}^2}$
In a meter bridge the point D is a neutral point (Fig).

Which of the following does not fit into a group:

A convex lens is used to form real image of an object on a screen. It is observed that even when the positions of the object and that screen are fixed there are two positions of the lens to form real images.  If the heights of the images are 4 cm and 9 cm respectively, the height of the object is

(a) 2.25 cm

(b) 6.00 cm

(c) 6.50 cm

(d) 36.00 cm