D.C Basic and network and electromagnetic theory. Part – 4

31. For maximum power transfer, internal resistance of source should be

A. Equal to load resistance

B. Less than the load resistance

C. Greater than the load resistance

D. none of the above

32. kirchoff’s law is applicable to

A. DC circuits only

B. passive networks only

C. AC circuits only

D. AC as well as DC circuits

33. Constant voltage source has

A. Low internal resistance

B. High internal resistance

C. Minimum current capacity

D. Minimum efficiency

34. A parallel plate capacitor with air as dielectric is charged and then disconnected from the supply the force between the plate is F if capacitor is immersed in a liquid dielectric having constant є then force between the plate will be

A. є²f

B. єf

C. F

D. F/є

35. The hot resistance of filament of bulb is higher than cold resistance of filament lamp because of temp. Co-officient of filament is

A. Negative

B. Zero

C. Infinite

D. Positive

36. Two capacitors each having capacitance C and breakdown voltage V are joined in series the capacitance and breakdown voltage of combination will be

A. 2C and 2V

B. 2C and V/2

C. C/2 and V/2

D. C/2 and 2V

37. The magnetic field required to reduce the residual magnetization to zero is called

A. Retentivity

B. Coercivity

C. Hysteresis

D. Saturation magnetism

38. Two resistor R1 and R2 give combine resistance of 4.5Ω when In series and 1Ω when in parallel the resistance are

A. 1Ω and 3.5Ω

B. 1.5Ω and 3Ω

C. 2Ω and 2.5Ω

D. 4Ω and 0.5Ω

39. Which of the following inductors will have least eddy current losses?

A. Air cored

B. Iron cored

C. Laminated iron cored

D. Wooden cored

40. The flow of electric current in a conductor is due to flow of

A. Electrons

B. Protons

C. Electrons and ions

D. Charged particles