HELP DESK SCIENCE (Holidays homework)

Dear Students! We are here to make our holidays homework much more easier.
Chemistry holidays homework:
1)Presentation related to syllabus chapters.
2)Assignment [Ch-Periodic classification of Elements]

Test of full syllabus.

Ask your queries, share the problems you are facing while completing your presentation. Please feel free to share your problems related any topic of physics or chemistry.
Comment on this post and please give us 2-3hours to reply!


  1. I have not understood the Physics concept "why planets don't twinkle" and "How different colors are deviated at different angles"... I referred to many websites, but didn't get appropriate answer! Help me on this!

  2. Answer to your first question:"why planets don't twinkle"
    Planets do not twinkle because planets are very close to the earth as compared to the stars. The planets act as extended sources of light. So the intensity of light we receive from the planets is very large. Therefore, the variation in the brightness of the planets is not detected. Hence, planets do not twinkle.
    Source: DINESH super simplified.
    for more info you can visit:

    Answer to your second question: I think here you are talking about different angles of deviation formed when white light passes trough glass prism.
    Speed of colour in a medium depends upon its wavelength. All the colours have different wavelength. The red colour has the longest wavelength and violet colour has the last wavelength. Therefore, red colour has the highest speed in the glass prism and the violet colour has the lowest speed in the glass prism. Hece, all colours of white light are refracted by different amounts while passing trough the glass prism. Therefore, all the colours have different angles of deviation.

  3. What is diffraction of light..not cleary understood??!!

  4. please visit this link rupali :