Calculate the total weeks for 4 topics: Topic 1=1 week, Topic 2=3 weeks, Topic 3=4 weeks, Topic 4=2 weeks. Then, calculate the percentage of each topic out of a total of 10 topics: Topic 1: 1/10100=10%, Topic 2: 3/10100=30%, Topic 3: 4/10100=40%, Topic 4: 2/10100=20%.

Step 1: Calculate the total duration for all topics. The durations for each topic are given: Topic 1 = 1 week Topic 2 = 3 weeks Topic 3 = 4 weeks Topic 4 = 2 weeks

Add the durations to find the total: $Total duration = 1 + 3 + 4 + 2 = 10 weeks$ The total duration is $\boxed{10 weeks}$.

Step 2: Calculate the percentage of the total duration for each topic. To find the percentage for each topic, divide its duration by the total duration and multiply by $100\%$.

For Topic 1: $Percentage for Topic 1 = \frac{1}{10} \times 100\% = 10\%$

For Topic 2: $Percentage for Topic 2 = \frac{3}{10} \times 100\% = 30\%$

For Topic 3: $Percentage for Topic 3 = \frac{4}{10} \times 100\% = 40\%$

For Topic 4: $Percentage for Topic 4 = \frac{2}{10} \times 100\% = 20\%$

The percentages for each topic are: • Topic 1: $\boxed{10\%}$ • Topic 2: $\boxed{30\%}$ • Topic 3: $\boxed{40\%}$ • Topic 4: $\boxed{20\%}$