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Electronics and Communication Engineering - Materials and Components

Exercise : Materials and Components - Section 5
46.
If v is velocity of electron, ε0 is absolute permittivity, m is mass of electron, e is charge on electron and r is the radius of orbit of electron in hydrogen atom, the stability of orbit requires the following equation to be satisfied
Answer: Option
Explanation:

Centrifugal force is equal to and coulomb force is equal to .

For stability they must be equal.

47.

Assertion (A): The equation D = ∈0∈rE is applicable only to isotropic materials.

Reason (R): In polycrystalline materials, the directional effects are absent.

Both A and R are true and R is correct explanation of A
Both A and R are true but R is not correct explanation of A
A is true but R is false
A is false but R is true
Answer: Option
Explanation:
No answer description is available. Let's discuss.
48.

Assertion (A): For a dielectric, P = ∈0(∈r - 1) E.

Reason (R): Dipole moment per unit volume is called polarization of dielectric.

Both A and R are true and R is correct explanation of A
Both A and R are true but R is not correct explanation of A
A is true but R is false
A is false but R is true
Answer: Option
Explanation:

The two statements are correct but independent of each other.

49.

Assertion (A): Ferrites are very useful at very high frequencies.

Reason (R): Ferrites have high permeability and high resistivity.

Both A and R are true and R is correct explanation of A
Both A and R are true but R is not correct explanation of A
A is true but R is false
A is false but R is true
Answer: Option
Explanation:
No answer description is available. Let's discuss.
50.
In a conductor the current flow is due to
holes
electrons
ions
electrons and ions
Answer: Option
Explanation:
No answer description is available. Let's discuss.
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