Theory:

9. One of the famous papers of 1905 was Einstein’s Special Theory of Relativity, according to which time and distance are not absolute. Indeed, two perfectly accurate clocks will not continue to show the same time if they come together again after a journey if one of them has been moving very fast relative to the other. From this followed the world’s most famous formula which describes the relationship between mass and energy:
E = mc2
(In this mathematical equation, E stands for energy, m for mass and c for the speed of the light in a vacuum (about 300,000 km/s).

When you sit with a nice girl for two hours, it seems like two minutes. When you sit on a hot stove for two minutes, it seems like two hours—that’s relativity. (Albert Einstein)
 
10. While Einstein was solving the most difficult problems in physics, his private life was unravelling. Albert had wanted to marry Mileva right after finishing his studies, but his mother was against it. She thought Mileva, who was three years older than her son, was too old for him. She was also bothered by Mileva’s intelligence. “She is a book like you,” his mother said. Einstein put the wedding off.
Explanation:
 
Einstein published one of his renowned papers called "Einstein's Special Theory of Relativity" in \(1905\). The theory brought revolutionary thought to the scientific world. According to the theory, the measurement of time and distance were not accurate; it depended on something else. When two perfectly accurate clocks come together after a journey, and one of them has been travelling very fast compared to the other, they will not continue to indicate the same time. This led to the development of the world's most famous formula for explaining the relationship between mass and energy.

The theory of relativity gave us the basic formula of physics "E = mc²". E stands for energy, m for the mass of the object and c for the speed of the light in a vacuum. The speed of light in a vacuum is almost 300,000 km/s. To put it into simpler words, Einstein gave an example for relativity. He says that sitting with a nice girl for two hours feels like two minutes and that sitting on a hot stove for two minutes feels like two hours.

Though he was solving the complicated sums in physics for the world, his personal life started becoming problematic. He began to fail in his own life. Albert Einstein thought of marrying Mileva Maric soon after finishing his studies. But his mother, Pauline Einstein, was against their marriage. Pauline thought of stopping the marriage for two reasons. At first, she thought that Mileva Maric, three years elder to Albert Einstein, was very old than him or too much matured than him. Then she was afraid of Mileva's intelligence, and she told Einstein that Mileva was similar to him and was like a book. As his mother was against it, he stopped his wedding with Mileva.
 
Meanings of the difficult words:
 
S.No
Words
Meanings
1
Accurate Of information, measurements, or statistics correct in details or exact
2
AbsoluteVery great or to the largest degree possible
3
UnravellingStarting to fail
4
IntelligenceThe ability to acquire and apply knowledge and skills
Reference:
National Council of Educational Research and Training (2006). Beehive. A Truly Beautiful Thing (pp. 46-53). Published at the Publication Division by the Secretary, National Council of Educational Research and Training, Sri Aurobindo Marg, New Delhi.