Answer:
C. The change of internal energy of a system is the sum of work and heat spent on it.
Explanation:
The law of conservation of Energy states that energy cannot be destroyed but can only be converted or transformed from one form to another. Therefore, the sum of the initial kinetic energy and potential energy is equal to the sum of the final kinetic energy and potential energy.
Mathematically, it is given by the formula;
Ki + Ui = Kf + Uf .......equation 1
Where;
Ki and Kf are the initial and final kinetic energy respectively.
Ui and Uf are the initial and final potential energy respectively.
The law of conservation of Energy is another way to describe the law of Thermodynamics. It states that the change of internal energy of a system is the sum of work and heat spent on it.
Mathematically, it is given by the formula;
ΔU = Q − W
Where;
ΔU represents the change in internal energy of a system.
Q represents the net heat transfer in and out of the system.
W represents the sum of work (net work) done on or by the system.
Answer: 
Explanation:
Given
Charge discharged 
time taken 
Current is given as rate of change of discharge i.e.

Therefore, the average current is 
Answer:
E = hv
Explanation:
- The photoelectric effect is a phenomenon when the electromagnetic waves of a particular wavelength strike on the metal plate like zinc, it ejects the free electrons.
- The ejected electrons have the kinetic energy and this energy is responsible for the electric energy.
- The kinetic energy of the emitted electrons is linked with the frequency of the incident rays.
- If the rays hitting the metal plate is below the minimum required threshold value, the photoelectrons are not ejected.
- The photoelectric equation is given by
E = hν - ∅
Where, ∅ is the minimum energy required to remove an electron.
Answer:
C:
Explanation:
either C or A but A seems unlikely after multiple attempts. Although the question doesn't make it clear whether the balance is electric either way it could be wrong in someway and seems to be the most likely.