Quantrex Quantrex AcademyJEE · NEET · NDA PYQs with solutions Open app
Concepts Of Physics MCQ Edition [Volume 2]PhysicsElectric Current through Gases

For a diode, the plate current is 20 mA when the plate voltage is 50 V or 60 V . What will be the current if the plate voltage is 70 V ?

Options

  1. A33 mA
  2. B24 mA
  3. C28 mA
  4. D20 mA

Correct answer

D. 20 mA

Step-by-step solution

Since the plate current is constant at 20 mA for plate voltages of 50 V and 60 V , the diode has reached its saturation state. In the saturation region, the plate current becomes independent of the plate voltage and depends only on the temperature of the cathode. Therefore, when the plate voltage is increased to 70 V , the plate current will remain at the saturation value of 20 mA .

Practice Electric Current through Gases on Quantrex Academy →

More from Electric Current through Gases

A pure tungsten cathode and a thoriated-tungsten cathode share the same geometrical dimensions and are operated at a common temperature. The current produced by the thoriated-tungsDetermine the ratio n(T)/n(1000 K ) for a tungsten emitter at temperatures T = 300 K , 2000 K , and 3000 K . Here, n(T) denotes the number of thermions emitted per second by the suWithin a discharge tube, the mean free path of electrons in the gas is inversely proportional to the internal pressure. The Crookes dark space occupies half the length of the dischAt 2000 K , the saturation current from a thoriated-tungsten cathode is 100 mA . Determine the saturation current for a pure-tungsten cathode that has the same surface area and opeWithin a discharge tube filled with a gas, a molecule undergoes ionization, causing an electron to be detached. An electric field of 5.0 kV m ⁻¹ is present in the region of the eveDetermine the factor by which the emission current changes when the temperature of a tungsten filament is increased from 2000 K to 2010 K . The work function of tungsten is 4.5 eV For tungsten, the constant A in the Richardson–Dushman equation is 60 imes 10^4 A m ⁻² K ⁻² , and its work function is 4.5 eV . An electric heater of 24 W is used to heat a tungsteWhen the plate voltage is 36 V , the power delivered in the plate circuit of a diode is 1.0 W . Determine the power delivered if the plate voltage is raised to 49 V . Assume the La Full Electric Current through Gases list All Concepts Of Physics MCQ Edition [Volume 2] PYQs