Question

Assertion (A): At a temperature of 1000 K, thermionic emission current is about 0.1 A/cm² of surface.Reason (R): Thermionic emission current is given by Ith = SA₀ T² e^(-Ew/kT).

a.

Both A and R are true and R is correct explanation of A

b.

Both A and R are true but R is not correct explanation of A

c.

A is true but R is false

d.

A is false but R is true

Answer: (a).Both A and R are true and R is correct explanation of A

Interact with the Community - Share Your Thoughts

Uncertain About the Answer? Seek Clarification Here.

Understand the Explanation? Include it Here.

Q. Assertion (A): At a temperature of 1000 K, thermionic emission current is about 0.1 A/cm² of surface.Reason (R): Thermionic emission current is given by Ith = SA₀ T² e^(-Ew/kT).

Similar Questions

Explore Relevant Multiple Choice Questions (MCQs)

Q. At room temperature, the current in intrinsic semiconductor is due to

Q. Ferroelectric materials are those which

Q. Assertion (A): Power loss in a conductor of resistance P = I²R.
Reason (R): When a conductor is carrying current with current density J as a result of applied field E, then heat developed/m³/ second = JE.

Q. Assertion (A): For Diamond, μᵣ = 1
Reason (R): Diamond is a diamagnetic material.

Q. For a paramagnetic material, susceptiblity increases with increasing temperature.

Q. Hydrogen is used in

Q. Assertion (A): Ferroelectric materials have spontaneous polarization.
Reason (R): Above curie temperature, ∈ = C/(T-ϴ) for ferro-electric materials.

Q. If e is the charge of an electron, R is the radius of its orbit and ω is the angular velocity of electron, the magnetic dipole moment μm of the orbit is |μm| = eωR².

Q. If a piece of wood is placed in a magnetic field

Q. The number of valence electrons in donor impurity are

Q. In a true valence crystal, the bonding between the atoms is accomplished by the sharing of valence electrons.

Q. Which of the following are donor impurities?

1. Gold
2. Phosphorus
3. Boron
4. Antimony
5. Arsenic
6. Induim

Select the correct answer using the following codes

Q. If n denotes principal quantum number, the angular quantum number l = 0, 1... (n - 1).

Q. Assertion (A): In a perfect capacitor, the current density is given by ω ∈₀E0∈'rcos(ωt + 90°), where ∈ᵣ' is real part of dielectric constant.
Reason (R): In a perfect capacitor, dielectric losses are zero.

Q. Assertion (A): For a solenoid having N turns, B = µ₀µᵣNI/L .
Reason (R): For all magnetic materials, B increases linearly with I.

Q. Assertion (A): If E is available energy state eV and EF is Fermi level, then probability of energy state E being occupied = 0.5.Reason (R): .

Q. A parallel plate capacitor has its length, width and separation doubled. It fringing effects are neglected, to keep the capacitance same, the dielectric constant must be

Q. Assertion (A): In imperfect capacitors, the current does not lead the applied ac voltage by 90°.
Reason (R): When subjected to ac fields, the dielectric constant can be expressed as ∈'r - j∈"r.

Q. In atomic physics, a state with l = 0 is called p state.

Q. If a sample of germanium and a sample of silicon have the same impurity density and are kept at room temperature

Recommended Subjects

Are you eager to expand your knowledge beyond Electronics and Communication Engineering? We've handpicked a range of related categories that you might find intriguing.

Click on the categories below to discover a wealth of MCQs and enrich your understanding of various subjects. Happy exploring!