Advertisements
Advertisements
Question
What role dose infra-red radiation play in maintain the Earth’s warmth
Advertisements
Solution
Visible light from the atmosphere is absorbed by the Earth’s surface and radiated as infrared radiation which gets trapped by greenhouse gases such as carbon dioxide and water vapour. This is how infrared radiation also plays an important role in maintaining the Earth’s warmth
APPEARS IN
RELATED QUESTIONS
A wave has wavelength 50 Å.
- Name the wave.
- State its speed in vacuum.
- State its one use.
Give one use of gamma rays.
Frequencies of Kα X-rays of different materials are measured. Which one of the graphs in the figure may represent the relation between the frequency v and the atomic number Z ?
The figure shows the intensity-wavelength relations of X-rays coming from two different Coolidge tubes. The solid curve represents the relation for the tube A in which the potential difference between the target and the filament is VA and the atomic number of the target material is ZA. These quantities are VB and ZB for the other tube. Then,
The distance between the cathode (filament) and the target in an X-ray tube is 1.5 m. If the cutoff wavelength is 30 pm, find the electric field between the cathode and the target.
(Use Planck constant h = 6.63 × 10-34 Js= 4.14 × 10-15 eVs, speed of light c = 3 × 108 m/s.)
Name the radiation of the electromagnetic spectrum which is used for the following:
To photograph internal parts of the human body and Give the frequency range
Name any two electromagnetic waves which have a frequency higher than that of violet light. State one use of each.
Answer briefly.
Why high-frequency carrier waves are used for the transmission of audio signals?
Find the photon energy in units of ev for electromagnetic wave if waves length 40 m. Given h = 6.63 × 10–34 J.
In an atom X, electrons absorb the energy from an external source. This energy “excites” the electrons from a lower-energy level to a higher-energy level around the nucleus of the atom. When electrons return to the ground state, they emit photons.
The figure below is the energy level diagram of atom X with three energy levels, E1 = 0.00eV, E2 = 1.78eV and E3 = 2.95eV. The ground state is considered 0 eV for reference. The transition of electrons takes place between levels E1 and E2.
- What wavelength of radiation is needed to excite the atom to energy level E2 from E1?
- Suppose the external source has a power of 100 W. What would be the rate of photon emission?
