1. Reverse bias applied to a junction diode [2003]

2. A solid cylinder and a hollow cylinder both of thesame mass and same external diameter are releasedfrom the same height at the same time on an inclinedplaneBoth roll down without slippingWhich one willreach the bottom first? [2000]

3. The device that can act as a complete electroniccircuit is [2010]

4. Two bodies have their moments of inertia I and 2Irespectively about their axis of rotationIf their kineticenergies of rotation are equal - their angular momentawill be in the ratio [2005]

5. Three masses are placed on the x-axis: 300 g atorigin - 500 g at x = 40 cm and 400 g at x = 70 cmThedistance of the centre of mass from the origin is:[2012M]

6. The moment of inertia of a body about a given axis is1.2 kg m 2Initially - the body is at restIn order toproduce a rotational kinetic energy of 1500 joule - anangular acceleration of 25 radian/sec 2 must be appliedabout that axis for a duration of [1990]

7. A gramophone record is revolving with an angularvelocity ωA coin is placed at a distance r from thecentre of the recordThe static coefficient of friction is μ.The coin will revolve with the record if: [2010]

8. In a p-n junction photocell - the value of the photoelectromotive force produced by monochromatic light isproportional to [2004]

9. In a junction diode - the holes are due to [1999]

10. When arsenic is added as an impurity to silicon - theresulting material is [1996]

11. A weightless ladder 20 ft long rests against africtionless wall at an angle of 60° from the horizontalA150 pound man is 4 ft from the top of the ladderAhorizontal force is needed to keep it from slipping.Choose the correct magnitude of the force from thefollowing [1998]

12. A wheel has angular acceleration of 3.0 rad/sec 2and an initial angular speed of 2.00 rad/secIn a time of2 sec it has rotated through an angle (in radian) of[2007]

13. For an electronic valve - the plate current Iand platevoltage Vin the space charge limited region are relatedas [1992]

14. The intrinsic semiconductor becomes an insulatorat [2001]

15. Choose the only false statement from the following[2005]

16. In a common base amplifier the phase differencebetween the input signal voltage and the output voltageis [1990]

17. A couple produces [1997]

18. Zener diode is used for [2005]

19. To use a transistor as an amplifier [1991]

20. In semiconductors - at room temperature [2004]

21. The moment of inertia of a thin uniform rod ofmass M and length L about an axis passing through itsmidpoint and perpendicular to its length is I 0Itsmoment of inertia about an axis passing through one ofits ends and perpendicular to its length is [2011]

22. For amplification by a triode - the signal to beamplified is given to [1992

23. To obtain a p-type germanium semiconductor - itmust be doped with [1997]

24. A constant torque of 1000 N-m turns a wheel ofmoment of inertia 200 kg-m2 about an axis through itscentreIts angular velocity after 3 seconds is [2001]

25. A circular disk of moment of inertia I t is rotating ina horizontal plane - its symmetry axis - with a constantangular speed ωiAnother disk of moment of inertia I b isdropped coaxially onto the rotating diskInitially thesecond disk has zero angular speedEventually both thedisks rotate with a constant angular speed ω fTheenergy lost by the initially rotating disk to friction is:[2010]