An electron enters a region where the electric field E is perpendicular to the magnetic field B. It will suffer no deflection if_________________?

Related Mcqs:

1. When an electron moving with a uniform speed in a vacuum enters a magnetic field in a direction perpendicular to the field the subsequent path of the electron is ___________________?

   A. a straight line parallel to the field
   B. a parabola in a plane perpendicular to the field
   C. a circle in a plane perpendicular to the field
   D. a straight line along its initial direction

2. When a particle of charge q and mass m enters into a uniform magnetic field B moving with a velocity v perpendicular to the direction for the field it describes a circular path of radius___________________?

   A. R=qB/mV
   B. R=mV/qB
   C. R=qmV/B
   D. R=qmB/V

3. The charged particle enters the uniform magnetic field in such a way that its initial velocity is not perpendicular to the field the orbit will be__________________?

   A. a circle
   B. a spiral
   C. an ellipse
   D. helix

4. Magnetic force acting on a unit positive charge moving perpendicular to the magnetic field with a unit velocity is called____________________?

   A. magnetic flux
   B. magnetic field intensity
   C. magnetic induction
   D. self inductance

5. If the plane of the rectangular coil is parallel to the magnetic field (i.e radial magnetic field) the torque on the coil is_____________________?

   A. τ = NIAB cosφ
   B. τ = NIAB sinφ
   C. τ = NIAB tanφ
   D. τ = NIAB

6. In the electron microscope, electric & magnetic fields are used as_______________?

   A. Electromagnetic gun
   B. Source of electromagnetic waves
   C. Deflecting charged particle
   D. Converging source of electrons

7. A current carrying conductor is placed in a uniform magnetic field parallel to it. The magnetic force experienced by the conductor is _____________________?

   A. F=1/B
   B. F=1/Bsinθ
   C. F/0
   D. F=1/Bcosθ

8. A particle of mass m charge q and speed V enters a uniform magnetic radius r. The radius r of the circle is_________________?

   A. independent mass m
   B. directly proportional to m
   C. directly proportional to q
   D. directly proportional to B

9. For confinement of electron in a box of radius 10-14m the electron, speed should be_____________?

   A. 107m/sec
   B. Should be greater than the speed of light.
   C. Be zero
   D. Not be wave-like

10. In bringing an electron towards the second electron, the electrostatic potential energy of the system

    A. Decreases
    B. increases
    C. remains the same
    D. becomes zero

    Submitted by: Tauseef Ali