Advertisements
Advertisements
Question
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.
Advertisements
Solution
Given:-
Heat produced/second = Power (P) = 200 W
Potential in the X ray tube, V = 20 kV
We know
Power, P = VI
Here, V = potential difference
I = current
But `l = (n e)/t`
Where, e = charge on electron
t = time
n = no of electrons
`therefore P = (n eV)/t`
`⇒ 200 = (n eV)/t`
`⇒ (n e"/"t)V = 200`
`⇒ I = 200/V`
`⇒ I = 200/(20 xx 10^3) = 10 "mA"`
APPEARS IN
RELATED QUESTIONS
To which part of electromagnetic spectrum does a wave of frequency 3 × 1013 Hz belong?
A radio can tune in to any station in the 7.5 MHz to 12 MHz band. What is the corresponding wavelength band?
Give a reason for the following:
Long-distance radio broadcasts use short-wave bands. Why?
Optical and radio telescopes are built on the ground but X-ray astronomy is possible only from satellites orbiting the earth. Why?
Arrange the following radiations in the order of their increasing wavelength:
X-rays, infrared rays, ratio waves, gamma ray and microwaves.
What is the range of the wavelength of the following electromagnetic waves?
(a)X-rays,
State the approximate range of wavelength associated with infrared rays.
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.
Name three properties of ultraviolet radiations which are similar to visible light.
Can X-rays be polarised?
If the current in the circuit for heating the filament is increased, the cutoff wavelength
The X-ray coming from a Coolidge tube has a cutoff wavelength of 80 pm. Find the kinetic energy of the electrons hitting the target.
(Use Planck constant h = 6.63 × 10-34 Js= 4.14 × 10-15 eVs, speed of light c = 3 × 108 m/s.)
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.)
Give one use of electromagnetic radiation in Microwaves.
Answer briefly.
Can we produce a pure electric or magnetic wave in space? Why?
Answer briefly.
Name the most harmful radiation entering the Earth's atmosphere from outer space.
Solve the numerical problem.
Calculate the frequency in MHz of a radio wave of wavelength 250 m. Remember that the speed of all EM waves in a vacuum is 3.0 × 108 m/s.
The frequency of e. m waves which is best suited .to observed of radius 3 × 10–4 his of the order of
SONAR emits which of the following waves?
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 ______.
