Answer:
The time is
![3.4*10^(-16)\ s](https://img.qammunity.org/2020/formulas/physics/college/tnain3cqzf5bsulmrwkp6zbw7ooj6di8tn.png)
Step-by-step explanation:
Given that,
Number of energy level n= 1
Energy E₁=4 eV
We need to calculate the time period
Using formula of time period
![T=(1)/(f)](https://img.qammunity.org/2020/formulas/physics/high-school/4gkvo9cbwtyubqfj0j1ztw08v8hhkh0bto.png)
![T=(h)/(E_(2)-E_(1))](https://img.qammunity.org/2020/formulas/physics/college/x4pjspf5y32szhpyquqcp6pem2zmzpw59o.png)
Where, E = energy
![E_(2)=4E_(1)](https://img.qammunity.org/2020/formulas/physics/college/q2bq2cs8b58enk1ra40ctj2br39rg943wu.png)
h = Planck constant
Put the value into the formula
![T=(6.63*10^(-34))/(3E_(1))](https://img.qammunity.org/2020/formulas/physics/college/ffs7hwddymjhxxzx0jeagto22tj27uvf82.png)
![T=(6.63*10^(-34))/(3*4*1.6*10^(-19))](https://img.qammunity.org/2020/formulas/physics/college/r2c5u1z90d4zprnn6s837dcb2ynm55c54b.png)
![T=3.4*10^(-16)\ s](https://img.qammunity.org/2020/formulas/physics/college/zrzuib6kj1vt7rlncjow0nxazwvgsrb78d.png)
Hence, The time is
![3.4*10^(-16)\ s](https://img.qammunity.org/2020/formulas/physics/college/tnain3cqzf5bsulmrwkp6zbw7ooj6di8tn.png)