All India Engineering / Architecture Entrance Examination (AIEEE)
CBSE Guess > AIEEE > AIEEE Papers > 2007 > Physics
AIEEE 2007 Physics
Q. 27. A charged particle moves through a magnetic field perpendicular to its direction. Then
- the momentum changes but the kinetic energy is constant
- both momentum and kinetic energy of the particle are not constant
- both, momentum and kinetic energy of the particle are constant
- kinetic energy changes but the momentum is constant
Sol: Magnetic force can not do any work, so kinetic energy remains constant.
Since initial velocity is perpendicular to magnetic field, hence momentum will change. Correct choice: (1)
Q. 28. Two identical conducting wires AOB and COD are placed at right angles to each other. The wire AOB carries an electric current 
and COD carries a current . The magnetic field on a point lying at a distance d from O, in a direction perpendicular to the plane of the wires AOB and COD, will be given by
Sol: Magnetic field due to AB and CD are 
respectively and are in mutually perpendicular direction 
.
Correct choice: (2)
Q. 29. The resistance of a wire is 5 ohm at
and 6 ohm at 
. The resistance of the wire at 
will be
- 2 ohm
- 1 ohm
- 4 ohm
- 3 ohm
Sol: 
Correct choice: (3)