**Problem 1 – Dumbbell in a magnetic field**

- Intermediate results – week 1
- Hint 1, Intermediate results – week 2
- Hint 2, Intermediate results – week 3
- Hint 3, Intermediate results – week 4
- Hint 4, Intermediate results – week 5
- Intermediate results – week 6
- Intermediate results – week 7
- Best solutions and final results

- Intermediate results – week 1
- Hint 1, Intermediate results – week 2
- Hint 2, Intermediate results – week 3
- Hint 3, Intermediate results – week 4
- Intermediate results – week 5
- Best solutions and final results

**Problem 3 – Oscillating octagon**

- Hint 0, Intermediate results – week 1
- Hint 1, Intermediate results – week 2
- Hint 2, Intermediate results – week 3
- Hint 3, Intermediate results – week 4
- Intermediate results – week 5
- Intermediate results – week 6
- Best solutions and final results

**Problem 4 – Shock wave in an electron gas**

- Hint 0, Intermediate results – week 1
- Hint 1, Intermediate results – week 2
- Hint 2, Intermediate results – week 3
- Hint 3, Intermediate results are the same as in week 3
- Hint 4, Intermediate results – week 5
- Intermediate results – week 6
- Summary of all the hints
- Intermediate results – week 7
- Intermediate results – week 8
- Best solutions and final results

**Problem 5 – Nonlinear circular resonator**

- Hint 0, Intermediate results – week 1
- Hint 1, Intermediate results – week 2
- Hint 2, Intermediate results – week 3
- Hint 3, Intermediate results are the same as for week 3
- Hint 4, Intermediate results – week 5
- Intermediate results – week 6
- Intermediate results – week 7
- Best solutions and final results

The competition started on December 27th, 2020, at **1 pm (GMT)**.

If you cannot access the registration link due to country-specific restrictions, please send your registration data (full name, date of birth, e-mail address, country, school or university, age group (university/pre-university) physics teacher (if pre-university) by email to physcs.cup@gmail.com.

The competition is sponsored by TalTech — Tallinn University of Technology. There is also a budget for awards.

**Distribution of problems.**

The first problem of Physics Cup – 2020 was published at **1 pm (GMT), 27th December 2020**. **At 1 pm (GMT) of the last Sunday of each month, between December 2019 and April 2020, a new problem is published at https://physicscup.ee**. The problems will be sent by e-mail to all the registered participants, too, but I cannot guarantee to send e-mails exactly at 1 pm GMT. Therefore, if you wish to access the problems as soon as possible, please read them online at physicscup.ee. I’ll send, however, the e-mail with each new problem and with each new hint as soon as I can.** **

**You will be informed if your solution submitted within the previous week was correct or not at 1 pm each Sunday** (registered participants will receive an e-mail with a non-public link to a page where all the results are listed).

Also, at **1 pm each Sunday, a new hint regarding the active problem is published** **at https://physicscup.ee**. Keep in mind that with each new hint, the base score for correct solutions is decreased by 0.1 pts (for more details, cf. https://physicscup.ee/participate/).

The final deadline for submitting solutions for the N-th problem is usually when the N+1st problem is published. However, depending on the number of correct solutions, the deadline may be extended by one or two weeks.

**About the results of Physics Cup TalTech 2020.**

I am very sorry about the long delay with the results of Physics Cup TalTech 2020 – the final results are still not out. The main reason behind this delay is that the COVID-19 disrupted my plans. As a result, I was unable to select the best papers for each problem in time. I can promise that (a) the best papers for the Physics Cup 2021 will be announced within two weeks from the last submission deadline for each of the problems; (b) the final results of the Physics Cup 2020, together with all the best solutions, will be announced during January 2021. – Jaan Kalda

**Call for problems.** Please send me any problem which you believe would be suitable for Physics Cup (use my personal email – my_surname@ioc.ee – JK)!