The frequency order for \(\gamma\) - rays (\(b\)), X – rays (\(a\)), and UV – rays (\(c\)) is:

1.	\( b>a>c \)	2.	\( a>b>c \)
3.	\( c>b>a \)	4.	\( a>c>b\)

If \(\lambda_{v}, \lambda_{x},\) and\(\lambda_{m}\) represent the wavelengths of visible light, \(x\text-\)rays and microwaves respectively, then:
1. \( \lambda_{m}>\lambda_{x}>\lambda_{v} \)
2. \( \lambda_{v}>\lambda_{m}>\lambda_{x } \)
3. \( \lambda_{v}>\lambda_{x}>\lambda_{m }\)
4. \(\lambda_{m}>\lambda_{v}>\lambda_{x}\)

Which of the following has the minimum wavelength?
1. X-rays
2. Ultraviolet rays
3. γ-rays
4. Cosmic rays

What is the cause of “Greenhouse effect”?

1. Infra-red rays

2. Ultraviolet rays

3. X-rays

4. Radio waves

If the frequency of an E.M. wave is 10 MHz, then its wavelength is:
1.  30 m
2.  300 m
3.  3 m
4.  none of the above

The velocity of electromagnetic waves is parallel to:

1. $\overrightarrow{\mathrm{B}}\times \overrightarrow{\mathrm{E}}$

2. $\overrightarrow{\mathrm{E}}\times \overrightarrow{\mathrm{B}}$

3. $\overrightarrow{\mathrm{E}}$

4. $\overrightarrow{\mathrm{B}}$

The biological importance of the ozone layer is: