For small size high frequency coils, the most common core material is air ferrit

CuriousTab

CuriousTab

Home Aptitude

Discussion

Home ‣ Electronics and Communication Engineering ‣ Materials and Components Comments

Question
For small size high frequency coils, the most common core material is
Options
A. air
B. ferrite
C. powdered iron
D. steel

Correct Answer

air

Materials and Components problems

Search Results

1. Assertion (A): For a magnetic material M = (?_r - 1) H, where M is magnetic dipole moment/m³, H is field intensity A/m and ?_r is relative permeability.
Reason (R): ?_r can have any value from 0 to hundreds of thousands.
Options
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

3. In terms of classical representation of electrons
Options
A. an atom is essentially empty
B. an atom is essentially full
C. an atom may be essentially empty or full depending on the material
D. an atom may be essentially empty or full depending on temperature

6. High frequency inductors and capacitors are commonly plated with silver. The main purpose of this is to
Options
A. reduce dc resistance
B. reduce ac resistance
C. increase dc resistance
D. increase ac resistance

8. Assertion (A): Metals are better heat conductors than insulators.
Reason (R): If is temperature gradient, Q is heat flow density and K is thermal conductivity, then Q = - K (dT/dx).
Options
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

9. Semiconductors have a positive temperature coefficient of resistivity.
Options
A. True
B. False

Comments

More in Electronics and Communication Engineering: