EC Engineering Materials and Components Online Test

Diamond is a paramagnetic material.

Which capacitor-store higher amount of energy?

Above ferroelectric curie temperature, spontaneous polarization in ferroelectric materials becomes stronger.

In paramagnetic materials

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

Assertion (A): Electronic and Ionic polarization in a polyatomic gas are independent of temperature.
Reason (R): The orientation polarization is independent of temperature.

Two materials having temperature coefficients of 0.004 and 0.0004 respectively are joined in series. The overall temperature coefficient is likely to be

The number of valence electrons in pentavalent impurity is

If the diameter of a wire is doubled, its current carrying capacity becomes

The law J = σE, where J is current density, σ is electrical conductivity and E is field strength is

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.

Material which lack permanent magnetic dipoles are known as

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

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

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

Which element exhibits the property of inertia?

For a permanent magnetic material

In a coaxial cable, braided copper is used for

The hysteresis phenomenon in ferromagnetic materials exists at all temperatures.

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

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

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

If the temperature of an extrinsic semiconductor is increased so that the intrinsic carrier concentration is doubled, then

There is no hysteresis phenomenon is any dielectric material.

In metals the valence electron wave functions are strongly perturbed by the presence of neighbouring atoms.

For a paramagnetic material, susceptiblity increases with increasing temperature.

Hydrogen is used in

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

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

If a piece of wood is placed in a magnetic field

The number of valence electrons in donor impurity are