QUESTIONS REVIEW OF FORCE ON CHARGEPARTICLE-12
Overview of Force on Charge Particle
Ques1: An electric charge enters in the electric field at right angles to the direction of electric field.
Ans: The electric charge will move along a parabolic path and straight path as it leaves the electric field
Ques2: What is Magnetic Lorentz force?-QUESTIONS REVIEW OF FORCE ON CHARGEPARTICLE-12
The magnetic Lorentz force is force that a charged particle experiences when it moves inside the magnetic field
It is directed perpendicular to the plane containing velocity and magnetic field vectors.
Ques3: Under what condition, does an electron moving in magnetic field experiences maximum force?
Ques4: Under what condition is the force acting on the charge moving through a uniform magnetic field is minimum-QUESTIONS REVIEW OF FORCE ON CHARGEPARTICLE-12
Ques5: State the principle of cyclotron.12
Ans: Cyclotron is based on the principle that when positive charge particles are subjected to a static magnetic field and an alternating electric field at high frequency, simultaneously and perpendicular to each other, then the charge particles follow the spiral path and come out of the device with sufficiently higher energy.
Ques6: Does time spent by a proton inside the Ds of the cyclotron depends upon?-QUESTIONS REVIEW OF FORCE ON CHARGEPARTICLE-12
- one the radius of the circular path,
- to the velocity of the proton.
Ans: No, the time spent by a proton inside the Ds of the cyclotron does not depend on both, the radius of the circular path and the velocity of the proton.
Ques7: What are the primary functions of the electric field and the magnetic field in a cyclotron?
Ans: The magnetic field makes the charged particle to move along the circular path and the oscillating electric field applied across the D’s accelerates the charge particle again and again.
Que8: The frequency of a charge circulating inside the Ds of a cyclotron is independent of the speed of the charge. Why?
Ans: The radius of the circular path inside D’s increases proportionally as the velocity of the charged particle does and so the increase in the velocity of the charged particle is exactly compensated by the proportional increase in the radius of the semicircular path. As a result, the time period of the charge, and hence its frequency, remains independent of the speed of the charge.
Ques9: Can a neutron be accelerated in a cyclotron? If, not Why?
Ans: No, neutrons cannot be accelerated in a cyclotron because the neutrons being neutral particles carry no charge and the electric field does not exert force on these neutral particles. The cyclotron can accelerate the charged particle only and is particularly suitable for protons and positive ions.
Ques10: Why do not charged particles moving at a right angle to the direction of an electric field follow a circular path?
Ans: The charged particles moving at right angles to the direction of the electric field experience force in the plane of the electric field. The force acts at a right angle to their path only at the instant, the charged particles enter the electric field and with the passage of time they no longer remain at right angles to the path. Since the force on the charge particles do not remain always perpendicular to the path, they do not move along a circular path. Ques11: Why does a charged particle moving at right angles to the direction of magnetic field follow a circular path?
Ques12: What is the work done by magnetic field on a moving charge and why?
Ques13: A charged particle in the plasma trapped in the magnetic field leaks out after a millisecond. What is the total
work done by the magnetic field during the time the particle is trapped?
Ans: As the force due to magnetic field on a moving charge is always in the perpendicular direction to its direction of motion.
No work is done by the magnetic field.
Ques14 Does a stationary charge experience force in an electrichttps://physicsmadesimple.in/electric-lines-of-force/https://physicsmadesimple.in/force-on-a-charge-particle/https://physicsmadesimple.in/electric-lines-of-force/ field?
Ques15: A beam of alpha particles and of protons, of the same velocity V, enters a uniform magnetic field at right angles to the field lines. The particles describe circular paths. Calculate the ratio of the radii of two paths.
Ques16: Electrons cannot be accelerated by cyclotron. Explain why:
Ans: Electrons are the lightest particles having very small mass (9.1 x 10-31 kg). Even a small increase in the energy of the electrons causes a very high increase in its speed. Due to the high speed, the electrons go quickly out of step with the oscillating electric field. This results a fast relativistic variation in mass of the electrons that gives rise to a serious problem when a cyclotron is used to accelerate the electrons.
