Answer:
![E'_n=4* E_n](https://img.qammunity.org/2020/formulas/physics/high-school/yk5i3buwo4c35dmzlzemm7alplfzasbu3a.png)
Step-by-step explanation:
The energy of a particle in one dimensional box is given by :
![E_n=(n^2h^2)/(8mL^2)](https://img.qammunity.org/2020/formulas/physics/high-school/qf34i0b6gwscgg2rxqpo4cvz5xrmtxjsqw.png)
n is the quantum number
h is the Planck's constant
m is the mass of particle
L is the length of box
If L' = L/2
Energy level is given by :
![E'_n=(n^2h^2)/(8mL'^2)](https://img.qammunity.org/2020/formulas/physics/high-school/uwjoo03wk2hg0ks255xy93iovrfslb5llv.png)
![E'_n=(n^2h^2)/(8m(L/2)^2)](https://img.qammunity.org/2020/formulas/physics/high-school/h5gdzlvq9qxzyqxxkury31jipetdbsm6yx.png)
![E'_n=4* (n^2h^2)/(8mL^2)](https://img.qammunity.org/2020/formulas/physics/high-school/caxmqapw5xqp0iwscj5xhrpkar1gjwluzh.png)
![E'_n=4* E_n](https://img.qammunity.org/2020/formulas/physics/high-school/yk5i3buwo4c35dmzlzemm7alplfzasbu3a.png)
So, if the same particle is placed in another box of length L/2, the energy should be four times the energy for the first box. Hence, this is the required solution.