Advertisements
Advertisements
Question
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
Solution
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
RELATED QUESTIONS
A plane electromagnetic wave travels in vacuum along z-direction. What can you say about the directions of its electric and magnetic field vectors? If the frequency of the wave is 30 MHz, what is its wavelength?
A wave has a wavelength of 10-3 nm. Name the wave.
Name three properties of ultraviolet radiations which are similar to visible light.
In a Coolidge tube, electrons strike the target and stop inside it. Does the target get more and more negatively charged as time passes?
Can a hydrogen atom emit characteristic X-rays?
Why is exposure to X-rays injurious to health but not exposure to visible light, when both are electromagnetic waves?
Moseley's Law for characteristic X-ray is √v = a(Z − b). Here,
The potential difference applied to an X-ray tube is increased. As a result, in the emitted radiation,
(a) the intensity increases
(b) the minimum wavelength increases
(c) the intensity remains unchanged
(d) the minimum wavelength decreases.
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 |
The Kα and Kβ X-rays of molybdenum have wavelengths 0.71 A and 0.63 A respectively. Find the wavelength of Lα X-ray of molybdenum.
Name the scientist who discovered Visible light
Name the radiation which can be detected by thermopile.
Choose the correct option.
The EM wave emitted by the Sun and responsible for heating the Earth’s atmosphere due to greenhouse effect is
An e.m. wave exerts pressure on the surface on which it is incident. Justify.
For television broadcasting, the frequency employed is normally
A radio can tune to any station in the 7.5 mHz to 12 MHz band. What is corresponding wave length band.
The electric field intensity produced by the radiations coming from 100 W bulb at a 3 m distance is E. The electric field intensity produced by the radiations coming from 50 W bulb at the same distance is ______.
The magnetic field of a beam emerging from a filter facing a floodlight is given by B0 = 12 × 10–8 sin (1.20 × 107z – 3.60 × 1015t) T. What is the average intensity of the beam?
Identify the electromagnetic wave whose wavelength range is from about 10-3 m to about 10-1 m. Write one use of this.
