Solutions to the Optics Worksheet

Here is the solution sheet for the optics worksheet I had posted earlier: worksheet – optics – solutions

I will be away from the Internet (again!) for another 10 days. Will be back to school on 15th May.

Read the first chapter of electricity – Electric Current (potential difference, current, resistance, Ohm’s law, series and parallel circuits)– from your textbook during this period.

I will give you a revision worksheet on electric current as soon as I’m back.


13 thoughts on “Solutions to the Optics Worksheet

  1. is it ok to write ‘the virtual image appears as a mirror image of the real image ‘ in the 10th question?

  2. i have a doubt with the diagram in question 9.
    when the light rays travel from air to the glass doesn’t it refract?or it does but you haven’t drawn it as it is not the main concept in the question?

    • real images are composed of light rays that converge to a focus for each point of the image. Thus they can be projected onto a screen. Virtual images have light rays which diverge as if they had come from points behind the source. Hence a screen will just be illuminated with unfocussed light.

  3. Questions from light (4A) :
    1. does sin i/ sin r = speed of light in medium 1/ speed of light in medium 2?

    2.on page 85) one of the factors that affect refractive index is given as “iii) the colour or wavelength of light”. How can colour and wavelength be used interchangeably? i thought colour was defined by frequency!

    3.How to find refractive index if angle i and angle r are given?

    4.Wavelength decreases with increase in refractive index. Increase in refractive index results in increase in lateral displacement. However, decrease in wavelength results in decrease in lateral displacement. how so?

    5.Is it increase of optical density or increase of DIFFERENCE of optical densities of the two media being compared that reults in increase of refractive index of the second medium?

    6. this is just maths- pls show me how 3X 10 to the power 8/ 6600X 10 to the power -10 = 4.54X 10 to the power 14. (example 6, 4A)

    7.This is Example 8 a) Could someone explain? I don’t know why but it just sounds wrong and confusing-
    Draw diagrams to show how light bends when it travels from liquid to glass and then liquid if i)light slows down in glass ii) light speeds up in glass.

    8. (Ex 4A, Question 15.) A monochromatic ray of light passes from air to glass. The wavelength of light in air is lambda, speed of light in air is c and in glass v. If absolute refractive index of glass is 1.5, find i) relationship between c and v ii) wavelength of light in glass.

  4. okay i guess u r not back yet so anybody help me with the answers to these questions(Q) and l confirm the statements (S) or the conclusions i came upon to be right or wrong:- (from electric current)
    S-current is speed of flow of charge.
    S-current flows from higher potential to lower (conventionally) but electrons flow from lower to higher
    S- potential at a point= the work done to bring a unit from 0 to that point.
    Q-as far as i understand potential difference is wen there is more in something than the other so “the p.d.between two points is equal to the work done in moving a unit positive charge from one point to the other”on pg 170 is confusing me (please explain )
    S-the slope of the I-V graph depends on the temp. of the conductor.
    S-it says super conductor is a substance of zero resistance at very low temp.So if temp. increases the resistance increases but it is still low compared to normal conductors( right!).
    S-external circuit is the normal circuit (circuit formed outside the battery ).
    Q-is there any thing called internal circuit?
    S-light bulbs glow because of high resistance which causes high temp. making the filament do SFL bulbs work do they also have a filament in them? normal yellow bulbs take up more electricity!
    Q-how do tube lights work?

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