Question
Define light. Name three important properties of light.
✓
Answer
Light is a form of energy, which produces the sensation of vision.It has following characteristics:
- It travels in straight lines and does not bend.
- It does not require any medium to travel i.e. it travels even in vacuum.
- Its speed in vacuum is maximum whose value is $3 \times 10^8 \mathrm{~m} / \mathrm{s}$.
- It exhibits phenomena of reflection, refraction and scattering.
- A white light consists of seven colors $(VIBGYOR).$
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Read the passage and answer the questions :
A student is conducting an experiment to observe the reaction of magnesium ribbon when it is burned in air. The student first cleans a small piece of magnesium ribbon using sandpaper and then ignites it using a flame. The ribbon burns with a dazzling white flame, and a white powdery substance is formed after the reaction. The student records these observations and continues to investigate the nature of the product formed by adding a small amount of water to the white powder.
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(b) The product will turn red litmus paper blue
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A student is conducting an experiment to observe the reaction of magnesium ribbon when it is burned in air. The student first cleans a small piece of magnesium ribbon using sandpaper and then ignites it using a flame. The ribbon burns with a dazzling white flame, and a white powdery substance is formed after the reaction. The student records these observations and continues to investigate the nature of the product formed by adding a small amount of water to the white powder.
Q.1. What is the white powder formed after burning magnesium ribbon?
(a) Magnesium sulphate
(b) Magnesium oxide
(c) Magnesium hydroxide
(d) Magnesium carbonate
Q.2. Which of the following will most likely happen after magnesium ribbon burns?
(a) The product will turn blue litmus paper red
(b) The product will turn red litmus paper blue
(c) The product will have no effect on litmus paper
(d) The product will blue litmus paper red as well as red litmus paper blue
Q.3. What is the result of adding water to magnesium oxide?
(a) It forms an acidic solution
(b) It forms a basic solution
(c) It forms a neutral solution
(d) It does not react with water
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| Incisors | ||
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