43. Traction systems is latest used in the world is
A. Three-phase 3.7 kV
B. 20 kV, 50 Hz, single-phase
C. 600 V, DC
D. 3 kV, DC

---

44. In a long distance electric train, power for lighting in passenger coach is provided
A. through locomotive
B. directly through overhead electric line
C. through individual generator of bogie and batteries
D. through rails

---

45. An ideal traction system should have
A. high starting tractive effort.
B. the locomotive is to run on metre gauge track
C. the locomotive is for shunting duty
D. the locomotive is for goods trains only.

---

46. Quadrilateral speed-time curve is the closer approximation for
A. main line service
B. suburban service
C. urban service
D. urban and suburban service

---

47. The specific energy consumption
A. increases with increase in maximum speed
B. decreases with increase in maximum speed
C. is independent of maximum speed.
D. none of these

---

48. For welding duty the rectifiers commonly used are
A. Mercury arc rectifiers
B. Selenium metal rectifiers
C. both and
D. none of the above

---

49. Electrodes having least diameter is
A. 20 SWG
B. 14 SWG
C. 8 SWG
D. 4 SWG

---