Concepts Of Physics MCQ Edition [Volume 2]PhysicsMagnetic Field
Doubly ionized helium ions are projected with a speed of 10 km s ⁻¹ perpendicular to a uniform magnetic field of magnitude 1.0 T . Calculate the force acting on an ion.
Options
- A3.2 10⁻¹⁹ N
- B6.4 10⁻¹⁵ N
- C3.2 10⁻¹⁵ N
- D1.6 10⁻¹⁵ N
Correct answer
C. 3.2 10⁻¹⁵ N
Step-by-step solution
The charge of a doubly ionized helium ion is q = +2e = 2 1.6 10⁻¹⁹ C = 3.2 10⁻¹⁹ C . The speed of the ion is v = 10 km s ⁻¹ = 10^4 m s ⁻¹ . The magnetic field is B = 1.0 T . The force acting on the ion moving perpendicular to the magnetic field is given by F = qvB . Substituting the values: F = 3.2 10⁻¹⁹ 10^4 1.0 F = 3.2 10⁻¹⁵ N