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: 1/10*100=10%, Topic 2: 3/10*100=30%, Topic 3: 4/10*100=40%, Topic 4: 2/10*100=20%.

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:

$$\text{Total duration} = 1 + 3 + 4 + 2 = 10 \text{ weeks}$$

The total duration is $\boxed{\text{10 weeks}}$.

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

For Topic 1:

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

For Topic 2:

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

For Topic 3:

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

For Topic 4:

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

The percentages for each topic are:

• Topic 1: $\boxed{\text{10\%}}$
• Topic 2: $\boxed{\text{30\%}}$
• Topic 3: $\boxed{\text{40\%}}$
• Topic 4: $\boxed{\text{20\%}}$