Advertisements
Advertisements
Question
If the earth did not have an atmosphere, would its average surface temperature be higher or lower than what it is now?
Advertisements
Solution
In the absence of an atmosphere, there would be no greenhouse effect on the surface of the Earth. As a result, the temperature of the Earth would decrease rapidly, making it chilly and difficult for humans to survive.
RELATED QUESTIONS
The small ozone layer on top of the stratosphere is crucial for human survival. Why?
Name the electromagnetic radiations used for (a) water purification, and (b) eye surgery.
State the approximate range of wavelength associated with visible light.
Name the waves produced by the changes in the nucleus of an atom.
If the potential difference applied to the tube is doubled and the separation between the filament and the target is also doubled, the cutoff wavelength
Moseley's Law for characteristic X-ray is √v = a(Z − b). Here,
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,

50% of the X-rays coming from a Coolidge tube are able to pass through a 0.1 mm thick aluminium foil. If the potential difference between the target and the filament is increased, the fraction of the X-rays passing through the same foil will be
The Kβ X-rays from certain elements are given below. Draw a Moseley-type plot of √v versus Z for Kβ radiation.
| Element | Ne | P | Ca | Mn | Zn | Br |
| Energy (keV) | 0.858 | 2.14 | 4.02 | 6.51 | 9.57 | 13.3 |
If the operating potential in an X-ray tube is increased by 1%, by what percentage does the cutoff wavelength decrease?
(Use Planck constant h = 6.63 × 10-34 Js= 4.14 × 10-15 eVs, speed of light c = 3 × 108 m/s.)
The stopping potential in a photoelectric experiment is linearly related to the inverse of the wavelength (1/λ) of the light falling on the cathode. The potential difference applied across an X-ray tube is linearly related to the inverse of the cutoff wavelength (1/λ) of the X-ray emitted. Show that the slopes of the lines in the two cases are equal and find its value.
(Use Planck constant h = 6.63 × 10-34 Js= 4.14 × 10-15 eVs, speed of light c = 3 × 108 m/s.)
Two waves A and B have wavelength 0.01 Å and 9000 Å respectively.
Name the two waves. compare the speeds of these waves when they travel in vacuum.
Identify the part of the electromagnetic spectrum used in
(i) radar and
(ii) eye surgery. Write their frequency range.
Name the radiation of the electromagnetic spectrum which is used for the following:
Radar and Give the frequency range.
Give one use of electromagnetic radiation in Ultraviolet radiation.
Electromagnetic waves with wavelength
- λ1 is used in satellite communication.
- λ2 is used to kill germs in water purifies.
- λ3 is used to detect leakage of oil in underground pipelines.
- λ4 is used to improve visibility in runways during fog and mist conditions.
- Identify and name the part of electromagnetic spectrum to which these radiations belong.
- Arrange these wavelengths in ascending order of their magnitude.
- Write one more application of each.
What happens to the intensity of light from a bulb if the distance from the bulb is doubled? As a laser beam travels across the length of a room, its intensity essentially remains constant. What geometrical characteristic of LASER beam is responsible for the constant intensity which is missing in the case of light from the bulb?
