What is the dielectric strength, coefficient of thermal expansion of glass with respect to porcelain insulators?

Read the given statements and conclusions carefully and choose which of the conclusions logically follows from the statement. Statements: I. All cups are porcelain. II. Some porcelain are white. Conclusion: 1. Some white are porcelain. 2. No cup is white.

A

Only conclusion 2 follows.

B

Both conclusions 1 and 2 follow.

C

Only conclusion 1 follows.

D

Neither conclusion 1 nor 2 follows.

Match the following classification of glasses with their specific uses: a. Soda lime glass 1. Used in the manufacturing of glass articles which have to withstand high temperatures. b. Potash lime glass 2. Used in the manufacturing of artificial gems, electric bulbs, lenses, Prisms, etc. c. Potash lead glass 3. Used in the manufacturing of glass tubes, laboratory apparatus, plate glass, window panels, etc. d. Common glass 4. Used in the manufacturing of medicine bottles

A

a - 1, b - 3, c - 2, d - 4

B

a - 3, b - 1, c - 2, d - 4

C

a - 3, b - 1, c - 4, d - 2

D

a - 1, b - 3, c - 4, d - 2

What is the dielectric strength of porcelain insulators?

A

60 kV/cm

B

140 kV/cm

C

50 kV/cm

D

40 kV/cm

Consider a three-phase. 50 Hz, 11 kV distribution system, Each of the conductors is suspended by an insulator string having two identical porcelain insulators. The self-capacitance of the insulator is 5 times the shunt capacitance between the link and the ground, as shown in the figure. The voltage across the two insulators are

A

e1 = 3.74 kV, e2 = 2.61 kV

B

e1 = 3.46 kV, e2 = 2.89 kV

C

e1 = 6.0 kV, e2 = 4.23 kV

D

e1 = 5.5 kV, e2 = 5.5 kV

Glass has lower tensile strength compared to porcelain insulators.

A

True

B

False

Consider the following statements.
1. Glass wool has tensile strength greater than steel.
2. Glass wool is fire proof.
3. Glass wool has high electrical conductivity and absorbs moisture.
4. Glass wool is used to prepare libre glass.
Which of the statements given above are correct?

A

1, 2, 3 and 4

B

1, 2 and 3

C

1, 2 and 4

D

3 and 4

What is the relation between linear expansion coefficient (α), Areal expansion coefficient (β) and volume expansion coefficient (ϒ)

A

α = β = γ

B

γ = 3 × α and β = 2 × α

C

\({\rm{\gamma }} = {\rm{\;}}\frac{{\rm{\alpha }}}{3}{\rm{\;and\;\beta }} = \frac{{\rm{\alpha }}}{2}\)

D

γ = 27 × α and β = 4 × α

Heat is being transferred by convection from water at 48 degree Celsius to glass plate whose surface is exposed to water at 40 degree Celsius. The thermal conductivity of water is 0.6 W/m K and the thermal conductivity of glass is 1.2 W/m K. The spectral gradient of temperature in the water at the water glass interface is 10 -4 K/m. The heat transfer coefficient in W/m2 K is

A

0.0

B

750

C

6.0

D

4.8

Which of the following is the correct relation for the coefficient of thermal expansion? (L is length after temperature change, L0 is original length, α is coefficient of thermal expansion. and ΔT is changing in temperature)

A

L = α(1 +L0 ΔT)

B

L = (1 + α ΔT)

C

L = L0(1 + α ΔT)

D

None of the above

What is the relation between the Coefficient of thermal expansion of concrete and the coefficient of thermal expansion in aggregates?

A

Equal

B

More than

C

Inversely proportional

D

Directly proportional

What is the dielectric strength, coefficient of thermal expansion of glass with respect to porcelain insulators?

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