The decrease in the mass of Uranium in a nuclear reactor operating at a power of $12 \text{ MW}$ per day is (Energy released in one ${}_{92}U^{235}$ fission is about $200 \text{ MeV}$):

$A$ power of $100 \ W$ is produced by the fission of $1 \ kg$ of $^{235}U$. For approximately how long will the energy production continue?

The example of nuclear fusion is

The Sun radiates energy continuously and maintains its brightness because:

Complete the following nuclear reaction:
${ }_{0}^{1} n+{ }_{92}^{235} U \rightarrow{ }_{92}^{236} U \rightarrow$ $\qquad$ $+{ }_{41}^{99} Nb+$ $\qquad$.

According to classical physics,$10^{-15} \ m$ is the distance of closest approach $(d_c)$ for fusion to occur between two protons. $A$ more accurate quantum approach states that $d_c = \frac{\lambda_p}{\sqrt{2}}$,where $\lambda_p$ is the de Broglie wavelength of a proton when they were far apart. Using this quantum approach,find the equation for the temperature $(T_c)$ at the center of a star. [Given: $M_p$ is the mass of the proton,$k$ is the Boltzmann constant,$e$ is the elementary charge]