11. Which of the following system is used for combined power and lighting load ?
(A) 3-phase, 4-wire
(B) 3-phase, 3-wire
(C) 1-phase, 2-wire
(D) 1-phase, 3-wire
12. The respective torque and slip of a 3-phase induction motor driven at synchronous speed are :
(A) Maximum and one
(B) Maximum and zero
(C) Zero and one
(D) Zero and zero
13. Zero If maximum value of a sine wave is 10 π, then its average value over one complete cycle is :
(A) 10
(B) zero
(C) 20 M
(D) 6.37
14. The tendency of alternating current to concentrate near the surface of a conductor is known as :
(A) Ferranti effect
(B) Corona
(C) Proximity effect
(D) Skin effect
15. Consider the following two statements :
(I) Rectifier converts A.C. supply into D.C. supply.
(II) Inverter converts D.C. supply into A.C. supply.
(A) Both statements (I) and (II) are wrong
(B) Both statements (I) and (II) are correct
(C) Statement (I) is correct, but (II) is wrong
(D) Statement (I) is wrong, but (II) is correct