- AHas its own persistent magnetic field.
- ✓Acts as a magnet when an electric current passes through it.
- CBoth $A$ and $B.$
- DNone of the above.
Electromagnets are a different from permanent magnets. Electromagnets are made of coils of wire with electricity passing through them.
When the coils of wire in an electromagnet have an electric current passing through them then magnetic field produced around the coils so the coils behave like a magnet.
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$A.$ The square of maximum velocity of photoelectrons varies linearly with frequency of incident light.
$B.$ The value of saturation current increases on moving the source of light away from the metal surface.
$C.$ The maximum kinetic energy of photo-electrons decreases on decreasing the power of LED (light emitting diode) source of light.
$D.$ The immediate emission of photo-electrons out of metal surface can not be explained by particle nature of light/electromagnetic waves.
$E.$ Existence of threshold wavelength can not be explained by wave nature of light/electromagnetic waves.
Choose the correct answer from the options given below:
Reason : Wavelength of light depends on refractive index of medium.