The aurora is caused when electrons and protons, moving in the earth's magnetic field of ≈5×10−5 t, collide with molecules of the atmosphere and cause them to glow. what is the radius of the circular orbit for (a) an electron with speed 1.0×106m/s and (b) a proton with speed 7.0×104m/s. what is re in meters and what is rp in meters?

a) 0.114 meters is the radius of the circular orbit for an electron with given speed.

b) 14.6 meters is the radius of the circular orbit for a proton with given speed.

Explanation:

Force on the charge particle :

Since, the particle is revolving around in a circular path ;

particle in constantly moving in circular path under action of magnetic field:

F = F'

Where :

r = radius of the circular path

m = mass of the particle

v = velocity of the particle

B = magnetic field

q = magnitude of  charge on the particle

a)  Velocity of the electron =  

Mass of electron = m =

Charge on an electron , q=

B =

Radius of the circular orbit for an electron with given speed =

0.114 meters is the radius of the circular orbit for an electron with given speed.

b)  Velocity of the proton =  

Mass of electron = m =

Charge on an electron , q=

B =

Radius of the circular orbit for a proton with given speed =

14.6 meters is the radius of the circular orbit for a proton with given speed.

14 days is the half-life of phosphorus-32

the best answer is d because the strong cohesion is caused by the ability of water molecules to undergo hydrogen bonding.

a is incorrect because when water solidifies, it becomes   ice, which expands and occupies a bigger volume for the same mass of water in its liquid state.

b is incorrect because water has high surface tension. besides bonding to itself it hydrogen bonds to other molecules at the top decreasing possibility for breaking of attractive forces.

c is incorrect because the water molecule has oxygen which is highly electronegative and so pulls the electron pair towards itself creating a dipole moment, making the molecule polar.

e is incorrect because water has strong adhesion, ability to stick to other molecules such as glass because of this molecules having stronger hydrogen bonding than water.