$CATEGORY: Science - Khan Academy/11.Human Eye and Colourful World/11.Human Eye and Colourful World--Atmospheric Refraction

//Multiple Choice

Why do stars appear to twinkle? {
    ~Due to their changing brightness
    =Due to atmospheric refraction of starlight
    ~Due to their rotation
    ~None of the above
}

Planets do not twinkle because\: {
    ~They are too close to Earth
    ~They emit their own light
    =They have a larger apparent size
    ~None of the above
}

The twinkling of stars is caused by\: {
    ~Light scattering
    =Atmospheric turbulence
    ~Reflection from the moon
    ~None of the above
}

Which phenomenon is responsible for the twinkling of stars? {
    ~Dispersion
    ~Reflection
    =Atmospheric refraction
    ~None of the above
}

The effect of twinkling is more noticeable for\: {
    ~Planets
    =Stars
    ~The Moon
    ~None of the above
}

//True or False

Planets twinkle more than stars. {F}

Stars twinkle because their light passes through layers of the Earth's atmosphere. {T}

The twinkling of stars can be explained by the dispersion of light. {F}

Planets appear to twinkle because they are very far from Earth. {F}

Atmospheric refraction is responsible for the twinkling of stars. {T}


//Match the following

Match the following items from Column A with their correct corresponding options from Column B\:
{
=Stars -> Twinkle due to atmospheric refraction
=Planets -> Do not twinkle due to larger apparent size
=Point sources of light -> Stars
=Extended Sources of light -> Planets
=Atmospheric turbulence -> Causes twinkling of stars
}


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