The core of a coil has a length of 10 cm. The self inductance is 8 mH. If the co

CuriousTab

CuriousTab

Home Aptitude

Discussion

Home ‣ Electronics and Communication Engineering ‣ Materials and Components Comments

Question
The core of a coil has a length of 10 cm. The self inductance is 8 mH. If the core length is doubled, all other quantities remaining the same, the self inductance will be
Options
A. 32 mH
B. 16 mH
C. 8 mH
D. 4 mH

Correct Answer

4 mH

Explanation

Inductance is inversely proportional to the core length.

Materials and Components problems

Search Results

1. In metals the valence electron wave functions are strongly perturbed by the presence of neighbouring atoms.
Options
A. True
B. False

2. Assertion (A): For Diamond, ?_r = 1
Reason (R): Diamond is a diamagnetic material.
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. If a piece of wood is placed in a magnetic field
Options
A. the magnetic field will not be affected
B. the magnetic lines of force will bend towards the piece
C. the magnetic lines of force will bend away from the piece
D. the flux may increase or decrease

5. If a sample of germanium and a sample of silicon have the same impurity density and are kept at room temperature
Options
A. both will have equal value of resistivity
B. both will have equal negative resistivity
C. resistivity of germanium will be higher than that of silicon
D. resistivity of silicon will be higher than that of germanium

6. Assertion (A): For a solenoid having N turns, .
Reason (R): For all magnetic materials, B increases linearly with I.
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

7. The law J = ?E, where J is current density, ? is electrical conductivity and E is field strength is
Options
A. Ohm's law
B. Gauss law
C. Ampere's law
D. Biot-Savart law

8. If ?_r' and ?_r" are the real and imaginary parts of complex dielectric constant ?_r, and ? is the loss angle. Then
Options
A.
B.
C. tan ? = ?'?"
D. tan ? = 1 - ?'

10. Assertion (A): Silicon is less sensitive to changes in temperature than germanium.
Reason (R): Cut in voltage in silicon is less than that in germanium.
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

Comments

There are no comments.

More in Electronics and Communication Engineering: