Physics
An electron microscope gives higher magnification than an optical microscope, because :

The electrons have more energy than the light particles
The wavelength of electrons is smaller as compared to the wavelength of visible light
The velocity of electron is smaller than that of visible light
It uses more powerful lenses

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Physics
'Mirage' is an example of

Total internal reflection of light only
Refraction and total internal reflection of light
Dispersion of light only
Refraction of light only

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Physics
Rainbow is due to

diffusion of sunlight through water droplets
refraction and reflection of sunlight by water droplets
absorption of sunlight in minute water droplets
ionisation of water deposits

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