Textbook Solutions: To Truly Understand a Rainbow | Gul Mohar Class 7: Book Solutions, Summaries & Worksheets PDF Download

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While Reading

b. He was brilliant and a college student.
Ans: Newton was a very intelligent student who studied in college. His sharp mind and love for learning made him stand out from others. He showed special interest in science and kept exploring new ideas.

Q2. Why do you think that people travelled to the countryside to escape the plague?
Ans: The plague spread fast in crowded cities where people lived close together. People moved to the countryside because it was less crowded and safer. They hoped to escape the deadly disease by living away from cities.

Q3. Unlike Newton, scientists of the time continued to …
Ans: The scientists of that period believed colour was a mixture of light and darkness. They accepted these old ideas without testing them. Newton, on the other hand, questioned such beliefs and tried to prove the truth.

Q4. The last sentence of paragraph 7 tells us that …
Ans:  The sentence shows Newton enjoyed questioning old beliefs and proving experts wrong. He was confident about his ideas. This habit of challenging traditional views helped him make new discoveries about light and colour.

Q5. Sir Chandrasekhara Venkata Raman FRS was an Indian physicist. He made a discovery that won him the 1930 Nobel Prize in Physics. Find out what his connection is to this text.
Ans: Sir Chandrasekhara Venkata Raman discovered the scattering of light, called the Raman Effect. This was closely related to Newton’s experiments on light and colours. Both scientists worked on understanding how light behaves and why colours are formed.

Q6. Underline the key sentence that tells us what Newton discovered about colours and white light.
Ans: The key sentence is: “Therefore, all the colours already existed in white light and the prism was simply fanning them out according to their ability to be bent.” This explains Newton’s main discovery about colours.

Q7. Use one word to describe how Newton set up his experiment and tested his theories.
Ans: Methodically.

Newton worked methodically. He was very systematic in his approach, planned carefully, and tested his ideas step by step. His way of working shows that patience and discipline are very important in scientific experiments.

Understanding the Text

A. Complete this flowchart.

Ans: Newton's Thought Process:

• The sparkling prisms caught Newton's eye – he wanted to discover the nature of colour.
• A white page with black writing did not appear coloured; it appeared grey.
• Newton didn't see how Aristotle or Hooke could be right.
• The prism was the perfect tool.
• Newton suspected that more accurate results could be had by placing the prism farther away.
• He wondered how the prism split the white light.
• A refracting object could bend each wavelength of light differently.
• Therefore, all the colours already existed in white light.

B. Answer these questions.

Q2. How did Newton feel about leaving London and living in the countryside? (para 3)
Ans: Newton did not feel sad about leaving London. He used the peaceful time in the countryside to study and think. The quiet surroundings gave him freedom to focus on experiments and scientific problems.

Q3. What did Newton do before he began an experiment? What does this tell us about the process of scientific discovery? (paras 4 and 5)
Ans: Before experiments, Newton observed things carefully, thought deeply, and chose meaningful problems. This shows that discovery begins with curiosity and patience. Careful thinking is very important for finding the right answers in science.

Q4. What did Aristotle and Robert Hooke believe about white light? (para 6)
Ans: Aristotle and Robert Hooke believed that white light was simple. They thought colours were made by mixing white and black. According to them, colour was not part of light itself but only an extra feature.

Q5. What did Newton observe during his experiment? What conclusion did he come to? (paras 9 and 10)
Ans: Newton saw that white light passing through a prism split into many colours. He concluded that colours are already present in white light. The prism only separates them by bending light, it does not create colours.

Q6. This was a significant discovery!
a. How is the discovery significant for scientists and scientific principles?
Ans: This discovery was very important for science. It proved that colour follows scientific rules and not old beliefs. It became the base of modern optics and encouraged scientists to study light more seriously.

b. How is it significant for Newton himself?
Ans: This was Newton’s first big discovery. It made him famous as a young scientist and gave him confidence. It also started his journey of making more important contributions in science later in his life.

Q7. Why did Newton conduct an 'experimentum crucis'? How did he do it? (paras 12 and 13)
Ans: Newton wanted to prove the prism did not create colour. He passed only green light from one prism into another. The light remained green, proving that colour already exists in white light, not in the prism.

Appreciating the Text

Q2. The writer asks some questions as the text progresses. What effect does this have on the reader? Does it help us follow along? Does it mimic Newton's thought process? How does this help in understanding the text?
Ans: The writer’s questions make the reader think step by step like Newton. They help us follow his thought process and understand his experiments better. This method keeps the reader engaged and makes the text easier to learn.