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9. Some sunglasses have photochromic lenses - Edexcel - GCSE Physics - Question 9 - 2019 - Paper 1
Question 9
9. Some sunglasses have photochromic lenses. Photochromic lenses are clear when the lenses are indoors but they darken in bright sunlight to reduce the effects of t... show full transcript
Worked Solution & Example Answer:9. Some sunglasses have photochromic lenses - Edexcel - GCSE Physics - Question 9 - 2019 - Paper 1
Step 1
Suggest a benefit of making the lenses go dark with ultraviolet light.
Answer
One benefit of making photochromic lenses darken in the presence of ultraviolet (UV) light is that they provide better protection for the eyes. By darkening, they reduce the amount of harmful UV radiation that penetrates through the lenses, thereby decreasing the risk of eye damage, such as cataracts or other UV-related eye conditions. This feature also enhances visual comfort and reduces glare, making them ideal for outdoor use.
Step 2
Calculate how many times further it is from Earth to Jupiter than from Earth to the Sun.
Answer
To find out how many times further it is from Earth to Jupiter than from Earth to the Sun, we can set up the following calculation:
- Time taken for radio waves from Jupiter = 40 minutes
- Time taken for light waves from the Sun = 8 minutes
Since the speed of light is constant, we can use the ratio of the times:
ext{Ratio} = rac{ ext{Time from Jupiter}}{ ext{Time from Sun}} = rac{40}{8} = 5
Therefore, it is 5 times further from Earth to Jupiter than from Earth to the Sun.
Step 3
State the property of electromagnetic radiation that is used in your answer.
Answer
The property of electromagnetic radiation used in this answer is the speed of light, which is constant in a vacuum. This property allows us to relate the time taken for electromagnetic waves to travel from one celestial body to another with their respective distances.