36. As compared to oscillators, an inverter provides
A. low voltage output
B. low frequency output
C. distortion less output
D. noiseless output

---

37.  During induction heating, the skin depth of penetration is proportional (f= frequency) to
A. f
B. f2
C.f3
D. none of the above

---

38. A device that cannot be triggered with voltage of either polarity is
A. Diac
B. Triac
C. SCS
D. All of the above

---

39.  In a three phase half wave rectifier, each diode conducts for a duration of
A. 180?
B. 120?
C. 90?
D. 60?

---

40. Which of the following finds applications in speed control of a de motor?
A. FET
B. NPN transistor
C. SCR
D. none of the above

---

41. The ward-leonard system is used for controlling the speed of
A. dc motors
B. single phase ac motors
C. three phase motors
D. universal motors

---

42. A device that does not exhibit negative resistance characteristics is
A. FET
B.UJT
C. tunnel diode
D. SCR

---