10 Question-Answer on force on moving charge
1. The mass of proton is 1847 times that of electron. If an electron and a proton are injected in a uniform electric field at right angle to the direction on the field, with the same kinetic energy, then
(a) The proton trajectory will be less curved than that of electron
(b) Both the trajectories will be straight
(c) Both the trajectories will be equally curved
(d) The electron trajectory will be less curved than that of proton
Ans: ( c)
2. The frequency of charged particle, moving at right angle to the magnetic field, is independent of
(a) The radius of circular trajectory
(b) The speed of particle
(c) Both ‘a’ and ‘b’
(d) The magnetic induction B.
Ans: ( c)
3. A beam of protons is moving parallel to a beam of electros. Both the beams will tend to:
(a) Repel each other
(b) Come closer
(c) Move more apart
(d) Either ‘b’ or ‘c’
Ans: (d)
4. A uniform electric field and uniform magnetic field are pointed in the same direction. If an electron is is projected in the same direction, the electron
(a) Velocity will increase in magnitude
(b) Velocity will decrease in magnitude
(c) Will turn to its left
(d) Will turn to its right
Ans: (b)
5. Radius of curvature of path of a charged particle in a uniform magnetic field, is directly proportional to
(a) Momentom of particle
(b) Intensity of the field
(c) Charge on the particle
(d) Energy of the particle
Ans: (a)
6. A cyclotron cannot accelerate
(a) Beta particles
(b) alpha particles
(c) high velocity gamma rays
(d) high velocity x-rays
Ans: (a,c,d)
7. A proton moving in a straight line enters a strong magnetic field along the field direction. How will its path and velocity change
(a) Path is circular but speed constant
(b) Path is same but velocity increases
(c) Path is same and velocity remains constant
(d) Path is same motion is retarded.
Ans: (c)
8. When a charged particle moves in a magnetic field, its K.E. always
(a) Increases
(b) Decreases
(c) Remains constant
(d) Increases or decreases which depend on direction of projection of particle.
Ans: ( c)
9. A beam of protons is deflected sideways. Could this deflection be caused by:
(a) Magnetic field only
(b) Electric field only
(c) Either electric or magnetic field
(d) Both electric and magnetic field
Ans : ( c)
10. A charge particle enters at 30˚ to the magnetic field. Its path becomes
(a) Circular
(b) Helical
(c) Elliptical
(d) Straight line
Ans: ( b)