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ECE :: Materials and Components

  1. Transformer oil is

  2. A.
    refined vegetable oil
    B.
    refined mineral oil
    C.
    mixture of vegetable and mineral oil
    D.
    none of the above

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  3. Assertion (A): Drift velocity of electrons is proportional to the applied electric field E.

    Reason (R): The average drift velocity per unit field is called mobility.

  4. 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

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  5. The materials having low retentivity are suitable for making

  6. A.
    temporary smagnets
    B.
    weak magnets
    C.
    permanent magnets
    D.
    both temporary and permanent magnets

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  7. If ∈r = ∈r' - jr" tan δ = .

  8. A.
    True
    B.
    False

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  9. Assertion (A): Electron concentration n, hole concentration p and charge concentration ni are related by ni2 = np.

    Reason (R): p type semiconductor is obtained by adding trivalent impurity to intrinsic semiconductor.

  10. 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

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