Motion of charged particles

Who discovered electron?

• Joseph John Thomson

• Max Planck

• Albert Einstein

• Issac Newton

Which of the following particles or radiations will not be deflected by a magnetic field? (Select all)

• alpha particle

• beta particle

• gamma radiation

• neutrino

Which equation is used to calculate the force acting on a charged particle of charge q that is moving with speed v at angle θ to magnetic field of flux density B?

• $F=Bqv$

• $F=Bqv\cos\theta$

• $F=Bqv\sin\theta$

• $F=Bqv\tan\theta$

A proton enters a region of uniform magnetic field at right angles. What is the shape of its path in the field?

• straight line

• circle

• parabola

• random

Magnetic force on a moving charged particle is always _______ to its direction of motion.

• perpendicular

• parallel

• opposite

• not related

An electron is travelling at a speed of 9.0×10⁷ m s⁻¹ at right angles to a uniform magnetic field (B=2.0 mT). Calculate radius of circle described by the electron. (e=1.6×10⁻¹⁹ C, m_e=9.11×10⁻³¹ kg.)

• 0.13 cm

• 0.26 cm

• 13 cm

• 26 cm

In a velocity selector, the strength of electric field is 2.4 kN C⁻¹ and the flux density of magnetic field is 20 mT. What is the speed selected?

• 0.12 m s⁻¹

• 8.3 m s⁻¹

• 1.2 × 10⁵ m s⁻¹

• 8.3 × 10⁻⁶ m s⁻¹

Who discovered that charge is quantised?

• Robert Downey Jr.

• Robert Milikan

• Robert Hooke

• Robert Boyle