Thursday, April 21, 2011

BSNL JTO EXAM 2011 SOLVED QUESTIONS

1. Modern capacitors which have high capacitance in small size use a dielectric of

(A) paper (B) rubber (C) ceramic (D) Mylar

2. The Maximum spectral response of the germanium and silicon is in the
(A) infrared region (B) ultraviolet region (C) visible region (D) x-ray region

3. For an insulating material, dielectric strength and dielectric loss should be respectively
(A) high and high (B) low and high (C) high and low (D) low and low.

4. In a distortion factor meter, the filter at the front end is used suppress
(A) odd harmonics (B) even harmonics (C) fundamental component (D) dc component

5. The coefficient of coupling between two air core coils depends on
(A) mutual inductance between two coils only (B) self inductances of the two coils only

(C) mutual inductance and self inductances of the two coils (D) none

6. For a parallel plate capacitor which is being charged out of the following the incorrect statement is
(A) Energy stored in the capacitor does not enter it through the connecting wire through the space around the wires and plates of capacitor.
(B) Rate at which energy flows into this volume is equal to the integration of the poynting vector over the boundary of the volume between the plates.
(C) The poynting vector points everywhere radially outward of the volume between plates.
(D) The poynting vector points everywhere radially in to the volume between the plates.

7. The presence of alkali oxides in alumino silicate ceramics is likely to result in dielectric breakdown due to
(A) Polarization (B) Conductivity (C) Structural homogeneties (D) Ionization

8. Which of the following will serve as a donor impurity in silion
(A) Boron (B) Indium (C) Germanium (D) Antimony

9. Electrical contact materials used in switches, brushes and relays must possess
(A) high thermal conductivity and high melting point (B) Low thermal conductivity and low melting point (C) High thermal conductivity and low melting point (D) Low thermal conductivity and high melting point.

10. An SCR can only be turned off via it’s
(A) cathode (B) anode (C) gates (D) none

11. Gold is often diffused into silicon PN junction devices to
(A) increase the recombination rate (B) reduce the recombination rate
(C) make silicon a direct gap semiconductor (D) make silicon semi-metal

12 With n nodes and b branches a network will have
(A) (b+n) links (B) b – n +1 links (C) b -n-1 links (D) b + n + 1 links

13. When a network has 10 nodes and 17 branches in all then the number of node pair voltages would be
(A) 7 (B) 9 (C) 10 (D) 45

14. In any atom the potential energy of an orbiting electron is
(A) always positive (B) always negative
(C) sometime positive, sometime negative (D) numerically less then its kinetic energy.

15. A delition MOSFET differs from a JFET in the sense that it has no
(A) channel (B) gate (C) P-N junctions (D) substrate

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