Super capacitor: Super capacitor is a high capacity capacitor with a capacitance value much higher than normal capacitors but with lower voltage limits. Such capacitors bridges the gap between electrolytic capacitors and rechargeable batteries.
In automobile, bus, train, crane, elevator such capacitors are used for regenerative braking, short term energy storage or burst-mode power delivery.
Super capacitors have many advantages over batteries: they are very low weight and generally don't contain harmful chemicals or toxic metal. They can be charged and discharged innumerable number of times without ever wearing out.
The disadvantage is that super capacitors aren't well-suited for long-term energy storage. The discharge rate of super capacitors is significantly higher than lithium-ion batteries, they can lose as much 10-20% of their charge per day due to self-discharge.
Self-discharge rate of Super capacitors:

Options

A. 10-20% of their charge per day
B. 1-2% of their charge per day
C. 0% of their charge per day
D. 100% of their charge per day

Explanation

To solve the question regarding the self-discharge rate of supercapacitors, we can follow these steps:

### Step-by-Step Solution:

1. **Understand the Concept**:
- Supercapacitors are high-capacity capacitors with a capacitance value much higher than normal capacitors but with lower voltage limits. They are used in various applications including regenerative braking and short-term energy storage.

2. **Identify the Key Information**:
- The paragraph states that supercapacitors can lose as much as 10-20% of their charge per day due to self-discharge. This is the crucial piece of information needed to answer the question.

3. **Review the Options**:
- The options provided are:
- A) 10-20% of their charge per day
- B) 1-2% of their charge per day
- C) 0% of their charge per day
- D) 100% of their charge per day

4. **Match the Information**:
- From the paragraph, we see that the self-discharge rate is explicitly mentioned as 10-20% of their charge per day.

5. **Select the Correct Option**:
- Comparing the options with the information from the paragraph, option A (10-20% of their charge per day) matches perfectly with the stated self-discharge rate.

6. **Eliminate Incorrect Options**:
- Options B (1-2%), C (0%), and D (100%) do not match the information provided in the paragraph and can be eliminated.

7. **Final Answer**:
- Therefore, the correct answer is **A) 10-20% of their charge per day**.