17 questions · timed · auto-graded
$\begin{aligned} & \text { Frequency }=500 MHz =500 \times 10^6 Hz \\ & \text { Wavelength }=60 cm =0.6 m \\ & \text { Velocity of wave }=\text { frequency } \times \text { wavelength }\end{aligned}$
$=500 \times 10^6 \times 0.6=3 \times 10^8 m / s$
The three radiations beyond the violet end of the visible spectrum are:
1) Ultraviolet radiations - 100 Å to 4000 Å
2) X-rays - 0.1 Å to 100 Å
3) Gamma rays - <0.1 Å
Water vapour, carbon dioxide, methane, and ozone are the major greenhouse gases present in the Earth's atmosphere.
These greenhouse gases absorb the infrared radiations in the Earth's atmosphere.
(b) Which of the radiation mentioned by you in part (a) has the highest penetrating power.
(b) Gamma rays have the highest penetrating power.
1) Ultraviolet radiations - 100 Å to 4000 Å
Use: For detecting purity of gems, eggs, ghee, etc.
2) X-rays - 0.1 Å to 100 Å
Use: For detecting fracture in bones, teeth, etc.