Answer:
Explanation:
Situations in which an electron will be affected by an external electric field but will not be affected by an external magnetic field
a ) When an electron is stationary in the electric field and magnetic field , he will be affected by electric field but not by magnetic field. Magnetic field can exert force only on mobile charges.
b ) When the electron is moving parallel to electric field and magnetic field . In this case also electric field will exert force on electron but magnetic field field will not exert force on electrons . Magnetic field can exert force only on the perpendicular component of the velocity of charged particles.
Situations when electron is affected by an external magnetic field but not by an external electric field
There is no such situation in which electric field will not affect an electron . It will always affect an electron .
To solve the problem it is necessary to apply the concepts related to Kepler's third law as well as the calculation of distances in orbits with eccentricities.
Kepler's third law tells us that
Where
T= Period
G= Gravitational constant
M = Mass of the sun
a= The semimajor axis of the comet's orbit
The period in years would be given by
PART A) Replacing the values to find a, we have
Therefore the semimajor axis is 
PART B) If the semi-major axis a and the eccentricity e of an orbit are known, then the periapsis and apoapsis distances can be calculated by
Answer:
An Atom's individual speed will change as it collides with other atoms, so we have to use an average.
Explanation:
In a gas a single atoms does an assortment of things during its time in the gas—sometimes it collides with an other atom gaining a lot of speed, sometimes losing a lot of speed in the collision, and sometimes just moving freely. Therefore: the motion of one individual atom is unpredictable, and it cannot be representative of all the the atoms in a gas, which is why we must average over all speeds of all atoms to find an average speed that allows us to calculate other quantities like temperature and pressure of the gas.
Hence, the second option <em>"an Atom's individual speed will change as it collides with other atoms, so we have to use an average" </em>stands correct.
