A micro-wave and an ultrasonic sound wave have the same wavelength. Their frequencies are in the ratio (approximately)

• 10⁶ : 1

• 10⁴ : 1

• 10² : 1

• 10 : 1

The ozone layer absorbs

• infrared radiations

• ultraviolet radiations

• X-rays

• γ-rays

All components of the electromagnetic spectrum in vacuum have the same

• energy

• velocity

• wavelength

• frequency

In fog, photographs of the objects taken with infrared radiations are more clear than those obtained during visible light because

• I-R radiation has lesser wavelength than visible radiation

• scattering of I-R light is more than visible light

• the intensity of I-R light from the object is less

• scattering of I-R light is less than visible light

35.

The speed of electromagnetic wave in vacuum depends upon the source of radiation

• increases as we move from γ-rays to radio waves

• decreases as we move from γ-rays to radio waves

• is same for all of them

• None of the above

Flash spectrum confirms a/an

• total solar eclipse

• lunar eclipse

• earthquake

• magnetic storm

X-rays, gamma rays and microwaves travelling in vacuum have

• same velocity and same frequency

• same wavelengths but different velocities

• same frequency but different velocities

• same velocity but different wavelengths

Pick out the correct statement from the following

• Mercury vapour lamp produces line emission spectrum

• Oil flame produces line emission spectrum

• Band spectrum helps us to study molecular structure

• Sunlight spectrum is an example for line absorption spectrum

The figure shows the energy level of certain atom. When the electron de excites from 3E to E, an electromagentic wave of wavelength λ, is emitted. What is the wavelength of the electromagnetic wave emitted when the electron de excites from $\frac{5\mathrm{E}}{3} \mathrm{to} \mathrm{E}$ ?

• 3λ

• 2λ

• 5λ

• $\frac{3\mathrm{\lambda }}{5}$

Electromagnetic radiation used to sterilise milk is 

• X-rays

• γ-rays

• UV rays

• Radio waves