J.J. Thompson is the scientist who recieved credit for discovering them.
Weight is different (but mass is the same)
Answer:
The fraction fraction of the final energy is stored in an initially uncharged capacitor after it has been charging for 3.0 time constants is

Explanation:
From the question we are told that
The time constant 
The potential across the capacitor can be mathematically represented as

Where
is the voltage of the capacitor when it is fully charged
So at


Generally energy stored in a capacitor is mathematically represented as

In this equation the energy stored is directly proportional to the the square of the potential across the capacitor
Now since capacitance is constant at
The energy stored can be evaluated at as


Hence the fraction of the energy stored in an initially uncharged capacitor is

The work done is 375 J
Explanation:
The work done by a force in moving an object is given by

where
F is the magnitude of the force
d is the displacement
is the angle between the direction of the force and the displacement
In this problem,
F = 75 N is the force applied to the couch
d = 5 m is the displacement
Assuming the force applied to the couch is parallel to the motion, 
And so, the work done is

Learn more about work:
brainly.com/question/6763771
brainly.com/question/6443626
#LearnwithBrainly
Answer:
(a) 2.33 A
(b) 15.075 V
Explanation:
From the question,
The total resistance (Rt) = R1+R2 = 3.85+6.47
R(t) = 10.32 ohms.
Applying ohm's law,
V = IR(t)..........equation 1
Where V = Emf of the battery, I = current flowing through the circuit, R(t) = combined resistance of both resistors.
Note: Since both resistors are connected in series, the current flowing through them is the same.
Therefore,
I = V/R(t)............. Equation 2
Given: V = 24 V, R(t) = 10.32 ohms
Substitute these values into equation 2
I = 24/10.32
I = 2.33 A.
Hence the current through R1 = 2.33 A.
V2 = IR2.............. Equation 3
V2 = 2.33(6.47)
V2 = 15.075 V