What is the relationship between the magnetic force on a moving charge and the electric field?

 qE + q(v x B)

True or False: The magnetic force on a charge moving parallel to the magnetic field is maximum.

False

The magnetic force on a charge moving parallel to the magnetic field is zero.

What is the Lorentz force equation?

 q(E + v x B)

What is the magnetic moment of a current loop defined as?

The magnetic moment M of a current loop is defined as M = NIA, where N is the number of turns, I is the current, and A is the area of the loop.

What is the equation for the magnetic field inside a long solenoid?

The magnetic field inside a long solenoid is given by B = μ₀nI, where μ₀ is the permeability of free space, n is the number of turns per unit length, and I is the current.

Fill in the blank: The torque τ on a magnetic dipole in a magnetic field is given by τ = ___.

M x B, where M is the magnetic moment and B is the magnetic field.

Riddle: I carry a current, create a field, but if you cut me, I become two. What am I?

A bar magnet.

What is the effect of increasing the temperature on the magnetic susceptibility of paramagnetic materials?

As temperature increases, the magnetic susceptibility of paramagnetic materials decreases.

What happens to the magnetic properties of ferromagnetic materials at their Curie temperature?

At the Curie temperature, ferromagnetic materials lose their magnetic properties and become paramagnetic.

True or False: The magnetic field lines of a bar magnet are always open loops.

False. The magnetic field lines of a bar magnet are closed loops, running from the north pole to the south pole.

An electron (m = 9×10⁻³¹ kg, q = 1.6×10⁻¹⁹ C) moves at 3×10⁷ m/s in 6×10⁻⁴ T (⊥ to B). Find radius of path.

r = mv/qB = 0.28 m.

According to Biot–Savart law, dB ∝ _____.
(a) I dl / r²
(b) I dl / r
(c) I dl / r³
(d) I dl × r

(c) I dl × r / r³