The energy gained by an electron as it is accelerated by an electric field is equal to the work done by the electric field itself, and this is equal to the product between the charge of the electron and the potential difference across which the electron traveled:

(1)
where e is the electron charge, and

is the potential difference between the initial and the final point of the electron, and this is equal to

(2)
where E is the intensity of the electric field and d is the distance covered by the electron. If we substitute (2) into (1), we find a final expression for the energy gained by the electron
Energy is the ability to do work.<span />
Answer:
option A
Explanation:
given,
Force = F
angle = θ
weight on suitcase = mg
distance = d
constant velocity so, acceleration a = 0
coefficient of friction = µ
Work done = ?
Work done is equal to force into displacement.
Friction act opposite to the force acting so, work done by frictional force will be negative.
frictional force will act into horizontal direction opposite to force.
here displacement is equal to d
now,
W = -F d cos θ
Hence,the correct answer is option A
Answer:
Explanation:
When the positively charged half shell is brought in contact with the electroscope, its needle deflects due to charge present on the shell.
When the negatively charged half shell is brought in contact with the positively charged shell , the positive and negative charge present on each shell neutralises each other .So both the shells lose their charges .The positive half shell also loses all its charges
When we separate the half shells , there will be no deflection in the electroscope because both the shell have already lost their charges and they have become neutral bodies . So they will not be able to produce any deflection in the electroscope.