Answer:
h f = W + KE
Input energy equals work function plus KE of emitted electron
W = 6.63E-34 * 2.5E15 - 6.3 * 1.6E-19
W = 6.63 * 2.5 * 10^-19 - 10.1 * E-19 ev (1ev = 1.6E-19 J)
W = (16.6 - 10.1)E-19 = 6.5E-19 J
h f = 6.5E-19 J for electrons to be emitted with zero KE
f = 6.5E-19 / 6.63E-34 = .98E-15 / sec = 9.8E-14 / sec (threshold)
Nowadays, most of the walkie talkies ... and all R/C models ... operate in the "Family Radio Service" (FRS) band. That's 46-49 MHz. The wavelength is 6.12-6.52 meters.
The current atomic model has a predicted area surrounding the nucleus where the electron could be located thanks to quantum physics, subatomic particles makes leaps through space, and an electron could even be a million miles from its nucleus.
So the correct option among the other answer choices are as follows: C.
Explanation:
The magnetic force acting on a current carrying wire in a uniform magnetic field is given by :

or

Where
is the angle between length and the magnetic field
The magnetic force is perpendicular to both current and magnetic field. It is maximum when it is perpendicular to both current and magnetic field.
So, the correct options are :
- The magnetic force on the current-carrying wire is strongest when the current is perpendicular to the magnetic field lines.
- .The direction of the magnetic force acting on a current-carrying wire in a uniform magnetic field is perpendicular to the direction of the field.
- The direction of the magnetic force acting on a current-carrying wire in a uniform magnetic field is perpendicular to the direction of the current.