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प्रश्न
Choose the correct option.
How does the frequency of a beam of ultraviolet light change when it travels from air into glass?
विकल्प
depends on the values of μ and ε
increases
decreases
remains same
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उत्तर
remains same
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संबंधित प्रश्न
Given below are some famous numbers associated with electromagnetic radiations in different contexts in physics. State the part of the electromagnetic spectrum to which each belongs.
(a) 21 cm (wavelength emitted by atomic hydrogen in interstellar space).
(b) 1057 MHz (frequency of radiation arising from two close energy levels in hydrogen; known as Lamb shift).
(c) 2.7 K [temperature associated with the isotropic radiation filling all space-thought to be a relic of the ‘big-bang’ origin of the universe].
(d) 5890 Å - 5896 Å [double lines of sodium]
(e) 14.4 keV [energy of a particular transition in 57Fe nucleus associated with a famous high resolution spectroscopic method (Mössbauer spectroscopy)].
State an additional use of the X-rays waves
What do you understand by the statement, "Electromagnetic waves transport momentum"?
State Moseley's law
What is the range of the wavelength of the following electromagnetic waves?
(a) Gamma rays.
What do you understand by the invisible spectrum?
Name two electromagnetic waves of frequency smaller than that of violet light. State one use of each.
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.
Which part of electromagnetic spectrum is used in radar systems?
When a Coolidge tube is operated for some time it becomes hot. Where does the heat come from?
Can X-rays be used for photoelectric effect?
X-ray from a Coolidge tube is incident on a thin aluminium foil. The intensity of the X-ray transmitted by the foil is found to be I0. The heating current is increased to increase the temperature of the filament. The intensity of the X-ray transmitted by the foil will be
(a) zero
(b) < I0
(c) I0
(d) > I0
Cutoff wavelength of X-rays coming from a Coolidge tube depends on the
(a) target material
(b) accelerating voltage
(c) separation between the target and the filament
(d) temperature of the filament.
Heat at the rate of 200 W is produced in an X-ray tube operating at 20 kV. Find the current in the circuit. Assume that only a small fraction of the kinetic energy of electrons is converted into X-rays.
The wavelength of Kα X-ray of tungsten is 21.3 pm. It takes 11.3 keV to knock out an electron from the L shell of a tungsten atom. What should be the minimum accelerating voltage across an X-ray tube having tungsten target which allows production of Kα X-ray?
(Use Planck constant h = 6.63 × 10-34 Js= 4.14 × 10-15 eVs, speed of light c = 3 × 108 m/s.)
The wavelengths of Kα and Lα X-rays of a material are 21.3 pm and 141 pm respectively. Find the wavelength of Kβ X-ray of the material.
(Use Planck constant h = 6.63 × 10-34 Js= 4.14 × 10-15 eVs, speed of light c = 3 × 108 m/s.)
Suppose a monochromatic X-ray beam of wavelength 100 pm is sent through a Young's double slit and the interference pattern is observed on a photographic plate placed 40 cm away from the slit. What should be the separation between the slits so that the successive maxima on the screen are separated by a distance of 0.1 mm?
Name the part of the electromagnetic spectrum which is:
Suitable for radar systems used in aircraft navigation.
Identify the part of the electromagnetic spectrum used in
(i) radar and
(ii) eye surgery. Write their frequency range.
Name two sources of infrared radiation.
Choose the correct option.
The EM wave emitted by the Sun and responsible for heating the Earth’s atmosphere due to greenhouse effect is
Answer briefly.
Name the most harmful radiation entering the Earth's atmosphere from outer space.
Calculate the wavelength of a microwave of a frequency of 8.0 GHz.
A bat moving at 10 ms−1 towards a wall sends a sound signal of 8000 Hz towards it. On reflection, it hears a sound of frequency f The value of f in Hz is close to (speed of sound = 320 ms−1)
For television broadcasting, the frequency employed is normally
The area to be covered for T.V telecast is doubled then the height of transmitting antenna (T.V tower) will have to be:-
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.
Choose the correct option related to wavelengths (λ) of different parts of the electromagnetic spectrum.
