Avelocity selector has a magnetic field of magnitude 0.28 t perpendicular to an electric field of magnitude 0.48 mv/m.(a) what must the speed of a particle be for it to pass through undeflected? )m/s(b)what energy must protons have to pass through undeflected? ( (c) what energy must electrons have to pass through undeflected? (

a) v = 1,714 10⁶ m / s , b)   K = 13.37 10⁻¹⁹ J , c)   K= 8.36 eV

Explanation:

a) A speed selector uses an electric force and a magnetic force that opposes it, so we can use the equilibrium equation

        - = 0

        =

      q E = q v B

      E = v B

      v = E / B

Let's calculate

     v = 0.48 10⁶ / 0.28

     v = 1,714 10⁶ m / s

b) the energy of the particles is kinetic energy

     K = ½ m v2

The mass of the proton is

    mp = 1.67 10⁻²⁷ kg

     K = ½ 1.67 10⁻²⁷ (1,714 10⁶)²

     K = 2.46 10⁻¹⁵ J

Let's reduce

    K = 2.45 10⁻¹⁵ J (1eV / 1.6 10⁻¹⁹J)

    K = 1.53 10⁴ eV

   K = 15.3 KeV

The mass of the electron

    me = 9.1 10-31 kg

     K = ½ 9.1 10⁻³¹ (1,714 10⁶)²

     K = 13.37 10⁻¹⁹ J

Let's reduce

    K = 13.37 10⁻¹⁹ J (1eV / 1.6 10⁻¹⁹ J)

    K= 8.36 eV

when jerome paddle in flowing river towards east the net speed of jerome will increase

so the net speed of jerome will be given as

now the speed of paul will be same as it is given as he is running on the ground

so

so here we can say since the speed of jerome is more so he will win the race

now as we know the distance so the time difference is given as

so jerome will reach first and the time difference will be 203.55 s or 3.4 min

3. dark matter

empty space could also be a simple vacuum