Explanation:
Given that,
(a) Speed, 
Mass of the electron, 
Mass of the proton, 
The wavelength of the electron is given by :



The wavelength of the proton is given by :



(b) Kinetic energy, 
The relation between the kinetic energy and the wavelength is given by :






Hence, this is the required solution.
Answer:
75 km/h
Explanation:
Speed = Distance divided by Time.
The train went a distance of 300 km in 4 hours. Therefore, the speed of the train is: 300 divided by 4 = 75 km/h
Answer:

The Magnitude of electric field is in the upward direction as shown directly towards the charge
.
Explanation:
Given:
- side of a square,

- charge on one corner of the square,

- charge on the remaining 3 corners of the square,

<u>Distance of the center from each corners</u>


∴Distance of center from corners, 
Now, electric field due to charges is given as:

<u>For charge
we have the field lines emerging out of the charge since it is positively charged:</u>

<u>Force by each of the charges at the remaining corners:</u>

<u> Now, net electric field in the vertical direction:</u>


<u>Now, net electric field in the horizontal direction:</u>


So the Magnitude of electric field is in the upward direction as shown directly towards the charge
.
RADIATION BELTS....... I think but it should be radiation belt
Answer:
0.00417 kW/K or 4.17 W/K
Second law is satisfied.
Explanation:
Parameters given:
Rate of heat transfer, Q = 2kW
Temperature of hot reservoir, Th = 800K
Temperature of cold reservoir, Tc = 300K
The rate of entropy change is given as:
ΔS = Q * [(1/Tc) - (1/Th)]
ΔS = 2 * (1/300 - 1/800)
ΔS = 2 * 0.002085
ΔS = 0.00417 kW/K or 4.17 W/K
Since ΔS is greater than 0, te the second law of thermodynamics is satisfied.