Answer
Integral EdA = Q/εo =C*Vc(t)/εo = 3.5e-12*21/εo = 4.74 V∙m <----- A)
Vc(t) = 21(1-e^-t/RC) because an uncharged capacitor is modeled as a short.
ic(t) = (21/120)e^-t/RC -----> ic(0) = 21/120 = 0.175A <----- B)
Q(0.5ns) = CVc(0.5ns) = 2e-12*21*(1-e^-t/RC) = 30.7pC
30.7pC/εo = 3.47 V∙m <----- C)
ic(0.5ns) = 29.7ma <----- D)
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 .
Unless if all forces cancel each other out , the object will no longer be in equilibrium
Explanation:
It is given that,
Initial speed of the automobile, u = 65 km/hr =
Final speed of the automobile, v = 0
Deceleration of the automobile, 
We need to find the distance covered by the car as it comes to rest. It can be calculated using third equation of motion as :



So, the acceleration of the car is
. Hence, this is the required solution.
"2 km/hr/s" means that in each second, its engines can increase its speed by 2 km/hr.
If it keeps doing that for 30 seconds, its speed has increased by 60 km/hr.
On top of the initial speed of 20 km/hr, that's 80 km/hr at the end of the 30 seconds.
This whole discussion is of <em>speed</em>, not velocity. Surely, in high school physics,
you've learned the difference by now. There's no information in the question that
says anything about the train's <em>direction</em>, and it was wrong to mention velocity in
the question. This whole thing could have been taking place on a curved section
of track. If that were the case, it would have taken a team of ace engineers, cranking
their Curtas, to describe what was happening to the velocity. Better to just stick with
speed.