Materials and Components - Section 1 (4)

Directions to Solve

Materials and Components - Section 1

25.

The attraction between the nucleus and valence electron of copper atom is

A.	zero
B.	weak
C.	strong
D.	either zero or strong

Answer: Option B

Explanation:

The valence electron, in copper atom, can be easily detached from nucleus.

26.

Assertion (A): Magnetic susceptibility of diamagnetic materials is much less than that of paramagnetic materials.

Reason (R): For diamagnetic as well as paramagnetic materials, μr is nearly equal to 1.

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: Option A

Explanation:

Magnetic susceptibility = (μr - 1)H.

For diamagnetic and paramagnetic materials magnetic susceptibility is very very small and μr = 1.

27.

The hysteresis phenomenon in ferromagnetic materials exists at all temperatures.

A.	True
B.	False

Answer: Option B

Explanation:

Hysteresis phenomenon exists below ferromagnetic curie temperature.

28.

In a coaxial cable, braided copper is used for

A.	conductor
B.	shield
C.	dielectric
D.	jacket

Answer: Option B

Explanation:

Braided material is used for shield.

29.

For a permanent magnetic material

A.	the residual induction and coercive field should be large
B.	the residual induction and coercive field should be small
C.	area of hysteresis loop should be small
D.	initial relative permeability should be high

Answer: Option A

Explanation:

Materials suitable for permanent magnet have large hysteresis loop.

Hence residual and coercive field are large.

30.

Which element exhibits the property of inertia?

A.	Resistance
B.	Capacitance
C.	Inductance
D.	Both resistance and inductance

Answer: Option C

Explanation:

Inductance opposes rise and decay of current. Hence it has the property of inertia.

31.

When an electric field E is applied to solid and liquid insulating materials, the internal field Ei acting at the location of atom is such that

A.	Ei = E
B.	Ei > E
C.	Ei < E
D.	Ei may be equal to or less than E

Answer: Option B

Explanation:

The actual field seen by an atom is larger than applied field.

32.

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

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

Answer: Option D

Explanation:

Resistivity of silicon is more than that of germanium.

Materials and Components - Section 1 (4)

Materials and Components - Section 1

Questions & Answers

Interviews

Jobs

Results

Admission

Admit Card

Answer Key