Advertisements
Advertisements
प्रश्न
When 40 kV is applied across an X-ray tube, X-ray is obtained with a maximum frequency of 9.7 × 1018 Hz. Calculate the value of Planck constant from these data.
(Use Planck constant h = 6.63 × 10-34 Js= 4.14 × 10-15 eVs, speed of light c = 3 × 108 m/s.)
Advertisements
उत्तर
Given:-
Potential applied to the X-ray tube, V = 40 kV
Frequency of the X-ray, v = 9.7 × 1018 Hz
Wavelength (`lambda`) is given by
`lambda = (hc)/(eV)`
Here,
h = Planck's constant
c = Speed of light
`e = 1.6 xx 10^-19`
`therefore lambda = (hc)/(eV)`
`⇒ lambda/c = h/(eV)`
`⇒ 1/v = h/(eV) ..................(∵ v = c/lambda)`
`⇒ h = (eV)/v`
`⇒ h = (40 xx 10^3)/(9.7 xx 10^18) xx e`
`⇒ h = 4.12 xx 10^-15 "eVs"`
APPEARS IN
संबंधित प्रश्न
To which part of the electromagnetic spectrum does a wave of frequency 5 × 1019 Hz belong?
What physical quantity is the same for X-rays of wavelength 10−10 m, red light of wavelength 6800 Å and radiowaves of wavelength 500 m?
The small ozone layer on top of the stratosphere is crucial for human survival. Why?
The wavelengths for the light of red and blue colours are roughly 7.8 × `10^7` m and 4.8 × `10^7` m respectively.
(a) Which colour has the greater speed in vacuum?
(b) Which colour has the greater speed in glass?
State the approximate range of wavelength associated with infrared rays.
When a Coolidge tube is operated for some time it becomes hot. Where does the heat come from?
Moseley's Law for characteristic X-ray is √v = a(Z − b). Here,
For harder X-rays,
(a) the wavelength is higher
(b) the intensity is higher
(c) the frequency is higher
(d) the photon energy is higher.
Name the scientist who discovered Infra-red waves
State three properties of ultra-violet radiation similar to visible light.
Choose the correct option.
How does the frequency of a beam of ultraviolet light change when it travels from air into glass?
What are the ultraviolet rays?
If the Earth did not have atmosphere, would its average surface temperature be higher or lower than what it is now? Explain.
A radio can tune to any station in the 7.5 mHz to 12 MHz band. What is corresponding wave length band.
Why does microwave oven heats up a food item containing water molecules most efficiently?
Arrange the following electromagnetic radiation in the ascending order of their frequencies:
X-rays, microwaves, gamma rays, radio waves
Which one of the following electromagnetic radiation has the least wavelength?
What is the wavelength range of electromagnetic radiation used in radio broadcast?
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?
