Arrange the following types of radiations in increasing order of frequency: $(a)$ radiation from microwave oven,$(b)$ amber light from traffic signal,$(c)$ radiation from $FM$ radio,$(d)$ cosmic rays from outer space,and $(e)$ $X$-rays.

Identify the correct statements from the following:
$I$) Isotopes of an element show different chemical behaviour
$II$) Lyman series of lines of hydrogen spectrum appear in $UV$ region
$III$) The oscillating electric and magnetic field components of electromagnetic radiation are perpendicular to each other and both are perpendicular to the direction of propagation of radiation

What is a black body?

$A$ gas absorbs a photon of $355 \ nm$ and emits at two wavelengths. If one of the emissions is at $680 \ nm,$ the other is at : ................. $nm$

Arrange the following types of radiation in increasing order of frequency:
$(a)$ radiation from microwave oven
$(b)$ amber light from traffic signal
$(c)$ radiation from $FM$ radio
$(d)$ cosmic rays from outer space
$(e)$ $X$-rays

Give the formulas for wave number and time period.