# X-RAYS PHYSICS REVISION IN PDF

X-RAYS

1. An X-ray tube is operating with an anode potential of 10kV and a current of 15.0 mA.
2. a) Explain how the
3. i) Intensity of X-rays from such a tube may be increased.
4. ii) Penetrating power of X- rays from such a tube may be increased
5. b) Calculate the number of electrons hitting the anode per second.
6. c) Determine the velocity with which the electrons strike the target.
7. d) State one industrial use of X-rays.
8. a) For a given source of X-rays, how the following would be controlled.
9. i) Intensity
10. ii) The penetrating power

iii)       The exposure to patients

1. b) An accelerating potential of 20kv is applied to an X-ray tube.
2. i) What is the velocity with which the electron strikes the target?
3. ii) State the energy changes that take place at the target.
4. Explain why X-rays are appropriate in study of the crystalline structure materials.
5. Name the metal used to shield X-rays operators from the radiation. Give reasons why it is used.
6. State the properties of X-rays, which makes it possible to detect cracks in bones.
7. State one difference between hard X-rays and soft X-rays.
8. A target was bombarded by electron accelerated by a voltage of 106 If all the K.E of the electrons was converted to X-rays, calculate:-
9. a) The K.E of the electrons
10. b) The frequency of the photons emitted.
11. An X-rays tube gives photons of 5.9 x 10-15 J of energy. Calculate:-
12. a) The wavelength of the photons.
13. b) The accelerating voltage
14. c) The velocity of the electrons hitting the target.
15. If accelerating voltage in an X-ray tube is 40kV, determine the minimum wavelength of the emitted X-rays. (Electronic charge = -1.6 x 1019C, planks constant = 6.6 x 10 -34Js, velocity of electromagnetic waves = 3.0 x 108ms-1)
16. State the purpose of cooling fins in the X-ray tube.
17. X-rays are produced by a tube operating at 1 x 104V. Calculate their wavelength.  (Take h= 6.6 x 10 -34 Js, e= 1.6 x 10-19C, c= 3×108ms-1)
18. State and explain the effect of increasing the EHT in an X- ray tube on the X-rays produced.
19. The figure below shows an X-ray tube.

1. a) Label the part marked Y.
2. b) How would one measure;
3. i) The intensity of the x-rays.
4. ii) The penetrating power of the x-rays.
5. c) Explain why the tube is highly evacuated.
6. d) An x-ray tube penetrating with anode potential of 10kv and amount of 15mA.
7. i) Calculate the number of electrons hitting the anode per second.
8. ii) Determine the speed with which the electrons hit the target.

(Change of an electron, Q= 1.6 x 10-19C; mass of electron Me = 9.1 x -31kg)

1. The figure below shows part of an X-ray tube.
2. a) i)         Explain briefly how X-rays are produced in the tube.
3. ii) Which material is used to  make the target?

iii)       Why is the anode made of thick copper metal.

1. iv) Why is it necessary to maintain vacuum inside the tube.
2. v) What effect will increasing p.d have on the X-rays produced? Explain your answer.
3. b) i) Explain why the tube of a cathode ray oscilloscope is made of thick

glass walls.

1. ii) The figure shows an AC voltage on a CRO screen.

Determine the peak voltage given that the sensitivity of the vertical axis is 8V/cm.

1. The figure below shows an x-ray tube

(a)       i)        Name the elements used in making the parts labelled A and B.

1. ii) Explain the use of the part labelled C.

iii)       Explain how the x-rays are produced.

(b)       The penetrating power of x-rays is normally varied depending on the intended use.

Explain how this is done.

1. c) The energy of x-ray is 1.989 x 10-14 Given that the speed of light is 3.0 x l08m/s and plank’s constant is 6.6 x 1034js find the wavelength of the x-rays.
2. (a) State one factor that affects the strength of an electromagnet.

(b) In Figure 12; the suspended metre rule is balanced by the magnet and the weight shown. The iron core is fixed to the bench.

• State and explain the effect on the metre rule when the switch is closed.
• What would be the effect of reversing the battery terminals?

(c)       A modern X-ray tube is shown below

(i)        Name the parts labeled A-D

A…………………………

B…………………………

C…………………………

D…………………………

(ii)       Give the functions of:

(a)       Shielding with lead                                                                                                    (b)       evacuating the tube

1. a) Name any two electromagnetic waves whose wavelength is shorter than visible light.
 B
 A

b)

 X rays

• The diagram above shows part of x-ray tube. Name parts

A

B

(ii)  Why is part B preferred?

1. c) (i) State two differences between x-rays and cathode rays.

(ii)  What is the effect on the wavelength of x-rays if the number of electrons hitting metal target are increased.

(iii)  What is the effect on wavelength of x-rays when p.d across the tube is decreased?

1. d) Calculate the maximum velocity of electrons that would produce x-rays of frequency 8.0 x 108Hz if only 20% of kinetic energy is converted to x-rays.

Take Planks constant = 6.63 x 10-34JS

1. In modern x-ray tube, why:
2. a) Is there a high vacuum in the tube? 1mk
3. b) Are cooling fins provided?
4. (a) Figure 6 below shows an X-ray tube.

(i) Name the elements used in making the parts labelled A and B.

(ii) Explain the use of the part labelled C.

(iii) Explain how the X-rays are produced.

(iv) Why is it necessary to maintain a vacuum inside the tube?

• The penetrating power of X-rays is normally varied depending on the intended use. Explain briefly how this is done.
• The energy of X-rays is 1.989 ´ 10ˉ14 Given that the speed of light is 3.0 ´ 108m/s and plank’s constant is 6.63 ´ 10-34JS. Find the wavelength of the X-rays.
• The figure below shows a wave form displayed on the screen of C.R.O when the time base is set at 20ms per division.

Determine the frequency of the signal.

1. (a) Figure 12 shows the features of an X-ray tube.

• Name the parts labelled A and B.
• State the functions of oil and copper anode.
• Explain why the tube is evacuated.
• Why is the anode made of a thick copper metal?
• Explain how a change in the potential across P changes the intensity of the X-rays produced in the tube.
• During the operation of the tube, the target becomes very hot. Explain how this heat is caused.
• What property of lead makes it suitable for use as shielding material?
• Explain why the tube of a cathode ray oscilloscope is made of a thick glass walls.

(b)(i) In a certain X-ray tube, the electrons are accelerated by a p.d. of 12000V.  Assuming all the energy goes to produce X-rays, determine the frequency of the X-rays produced.  (Plank’s constant h = 6.62 x 10 34Js and charge on an electron, e = 1.6 ´ 10-19C).

1. (a)X- rays are used for detecting cracks inside metal beams
• State the type of the X- rays used

(ii)  Give a reason for your answer in (i) above

• Figure 4 shows the features of an X- ray tube

• Name the parts labeled A and B
• Explain how a change in the potential across PQ changes the intensity of the X- rays produced in the tube.
• During the operation of the tube, the target becomes very hot. Explain how this heat is caused
• What property of lead makes it suitable for use as shielding material?
• In a certain X- ray tube, the electrons are accelerated by a Pd of 12000V. Assuming all the energy goes to produce X- rays, determine the frequency of the X- rays produced. (Plank’s constant h= 6.62 x 10-34 Js and charge on an electron, e = 1.6 x 10-19C).
• What effect will increasing p.d have on the x-rays produced explain your answer.
• What property of lead makes it suitable for use as shielding material?
1. The figure below is of an x-ray tube

(a) Explain how x-rays are produced by the tube

(b)             Explain briefly the energy changes that take place when the x-ray tube is operating

(c) Why is it necessary to maintain a vacuum inside the tube?

(d)             The accelerating voltage of an x-ray tube is 12V. Calculate the speed of the electron on reading the anode. (Charge to mass ratio of an electron  = 1.76 x 1011

1. a) The diagram below shows part of X – rays tube.

Name parts:          P, Q.

1. b) i) What is the effect on the wavelength of X – rays if the number of electrons hitting metal target are increased.
2. ii) What is the effect on wavelength of X –rays when p.d across the tube is decreased?
3. c) Calculate the maximum velocity of electrons that would produce x-rays of frequency 8.0×108HZ if only 20% of kinetic energy is converted to x – rays.(Take planks constant = 6.63 x 10-34 JS and mass of electron = 9.1 x 10-31 kg). (3mks)
4. d) An x-ray tube operating at a potential difference of 50KV has a tube current 20mA.Calculate.
5. i) The electric power input.
6. ii) The number of electrons hitting the target per second given that   e = 1.6 x 10-19.

iii) The velocity of electrons when they hit the target.

1. Figure below shows an x-ray tube
2. a) i) Name the elements used in making the parts labeled A and B.
3. ii) Explain the use of the part labeled C.

iii)       Explain how the x-rays are produced.

1. iv) Why is the x-ray tube evacuated?
2. b) The penetrating power of x-rays is normally varied depending on the intended use. Explain briefly how this is done.

c). An x-ray tube is operating with an anode potential of 20KV and a current of 40mA. Determine the number of electrons hitting the target per second.  (The charge of an electron is 1.6 x 10-19C)

1. (a) Explain how the grid is used to control the brightness of a spot in a CRO.

(b) State the difference between hard and soft X-rays.              (1mark)

(c) The following diagram represents an X-ray tube. The anode is made of thick copper metal with embeded tungsten.

• What property makes tungsten suitable for use as a target?
• Why is it necessary to maintain a vacuum inside the tube?
• Why is the anode made of thick copper metal?
• What effect will the increase in the p.d. between the anode and the filament have on the X-rays produced?
• An accelerating potential of 20kV is applied to an X-ray tube. What is the velocity with which the electrons strike the target? (e=1.6×10-19C, me = 9.1 x 10-31kg)
1. c) i) List two properties of x-rays

(ii) The figure shows a simplified illustration of an x-ray tube

Explain the following features in an x-ray tube

1. Low pressure

iii) Explain the adjustment that can be made to obtain hard x-rays

1. State the factor that determines the hardness of the X – rays produced in an X – ray tube.
2. In an X- ray tube it is observed that the intensity of X- rays increases when a potential difference across the filament is increased. Explain this observation
3. State one industrial use of X – rays
4. State the energy transformation when fast moving electrons are suddenly stopped by a target in an X- ray tube.
5. Name the metal used to shields X – rays operators from the radiation. Give a reason why it is used.
6. State and explain the effect of increasing the E.H.T in an x-ray tube on the X-rays produced.
7. State the property of X-rays, which makes it possible to detect cracks in bones.
8. Give a reason why the target in an X-ray tube is made of tungsten or molybdenum.
9. State the difference between hard X-ray and soft X-rays.
10. The accelerating potential of a certain X-ray tube is increased. State the change observed on the X-rays produced.
11. (a) X- rays are used for detecting cracks inside metal beams

(i)State the type of the X- rays used

(ii)Give a reason for your answer in (i) above

(b)Figure below shows the features of an X- ray tube

• Name the parts labelled A and B
• Explain how a change in the potential across PQ changes the intensity of the X- rays produced in the tube.
• During the operation of the tube, the target becomes very hot. Explain how this heat is caused
• What property of lead makes it suitable for use as shielding material?

(c)In a certain X- ray tube, the electrons are accelerated by a Pd of 12000V. Assuming all the energy goes to produce X- rays, determine the frequency of the X- rays produced. (Plank’s constant h= 6.62 x 10-34 Js and charge on an electron, e = 1.6 x 10-19C).

1. The figure below shows the essential components of an X-ray tube.

• How are the x-rays produced?
• How are produced electrons accelerated towards the anode?
• Suggest with a reason which material is used to make metal target.
• How is cooling achieved in this kind of x-ray machine?
• Why would it be necessary for the target to rotate during operation of this machine?
• Why is the machine surrounded by lead shields?
1. State the factor that determines:
1. The quality of an x-ray beam
2. The hardness of the x-rays produced in an x-ray tube.
2. State the function of oil in an x-ray tube, and explain why it uses instead of water.
3. The accelerating potential in an x-ray machine is 200kV. Calculate:
• Kinetic energy of the electrons arriving at the target.
• The maximum frequency of the x-rays produced by the tube.
• If 0.1% of the electron energy is converted into x-rays, determine the minimum wavelength of the emitted x-rays.
4. (i) The diagram below shows simplified diagram of an x-ray tube,
 Figure 8

(a) Name the parts A, B, and C.

(b) What adjustments would be made to:

(i) Increase the penetrating power of the x-rays produced.

(ii) Increase the intensity of the rays produced.

(c) Name a suitable material for the part marked B and give a reason for your choice.

(d) Name a suitable material for the part marked C and sate its purpose.

(e) Why is it necessary to maintain a vacuum inside the tube?

(f) State one use of x-rays in the following areas; –

(i) In medicine

(ii) In Industry.

 EHT
1. a) The figure shows the circuit of a modern X-ray tube

 Evacuated tube

• Indicate the path of the X-ray beam supplied by the tube
• Name the part labeled C and state its function
• If the tube above is operated at an accelerating potential of 100kV and only 0.05% of the energy of the electrons is converted to X – rays, calculate the wave length of the generated X-rays. (Take electric charge e = 1.602 x10-19C, planks constant h = 6.63 x 10-34 Js, and speed of light c = 3.0 x 108m/s)
• State two properties of X-rays
• State one industrial application of X-rays
1. Figure below shows an x-ray tube:

 •

(a) Indicate on the diagram the path of x-ray beam supplied by the tube

(b) Why is M set at angle of 45o relative to the electron beam?

(c) Name a suitable metal that can be used for part M and give a reason for your choice

(d) State how the following can be controlled:-

(i) Intensity

(ii) Penetrating power                                                                                                                        (iii) The exposure to patients

(e) An x-ray tube is operating with an anode potential of 12Kv and a current of 10.0m.A:

(i) Calculate the number of electrons hitting the anode per second

(ii) Determine the velocity with which the electrons strike the target

(iii) State one industrial use of x-rays

1. Below shows an x-ray tube

1. a) i) Name the elements used in making the parts labeled A and B.

A…………………………………………………………………….

B ……………………………………………………………………

1. ii) Explain the use of the part labeled

iii) Explain how the x-rays are produced.

1. iv) Why is the x-ray tube evacuated?
2. b) The penetrating power of x-rays is normally varied depending on the intended use. Explain briefly how this is done.
3. c) The energy of x-ray is 2.089 x 10-14 Given that the speed of light is 3.0×108m/s and plank’s constant is 6.6 x 10-34Js, find the wavelength of the x-rays.
4. (a) Figure 10 below shows the features of an X-ray tube.

Fig. 10

1. i) Name the parts marked with letters A and B

A…………………………………………………………….

B ………………………………………………………………

1. ii) Explain how a change in the potential across PQ changes the intensity of x-rays produced in the tube.

iii) During the operation of the tube, the target becomes very hot. Explain how this heat is caused.

1. iv) State the property of lead that makes it suitable for use as shielding material .
2. b) In an certain x-ray tube, the electrons are accelerated by a p.d of 12,000V. Assuming all the energy goes to produce x-rays, determine the frequency  of the x-rays produced (planks’s constant ,h = 6.62 X 10-34 Js and charge on an electron, e = 1.6 x 10-19c).
3. 8 shows apparatus used to produce X-rays

(a)       (i)        Name the parts marked X and Y

X_______________________           Y________________________

(ii)       Suggest a suitable material for the metal target. Give a reason to support your

(b)       (i)        Give a reason why X-ray tube is evacuated.

(ii)       How is the intensity of X-rays increased?

(c)       Calculate the minimum wavelength of X-rays emitted when electrons through 30 kV             stricke             target. (Take electronic charge, e = 1.6 x 10-19 C, Planck’s constant h = 6.63 x 10-34      Js and speed of light c = 3.0 x 108 ms-1)

1. (a) State two properties of X – rays

(b) (i)        In an x – ray tube the target is made of tungsten. Explain

(ii)       State the effect on the nature of x – rays when the heater current is increased

(c)       In an x – ray tube operating at 100kV, the tube current is 20mA.

(i)        Determine the number of electrons hitting the target every second

(Charge of an electron = 1.6 x 10-19C)

1. ii) If only 0.49% of the electrons is converted to x – rays, calculate the quantity of

heat produced per second.

(d)       (i)        Give two uses of x – rays

(ii)       State one danger of x – rays

E.H.T.

B

Low pd

A             D

X-rays

The diagram above shows an x-ray tube

1. State the functions of A and C.
2. What adjustment on the x-ray tube will:
• Increase the hardness of the x-rays
• Reduce the intensity of the x-rays.
1. (i) An x-ray tube has an accelerating p.d of 50kv. Determine the shortest wavelength of in its x-ray beam. (Planks constant charge on an electron = 1.6 x 10-19c average velocity of light,

c=3.0 x 108 ms-1)           e = 1.6 x 10-19  C                                 h = 6.63 x 10-34Js

• An isotope of uranium 238U decays by emitting an alpha particle and a beta particle

92

forming a new element M. Write down an equation for the reaction.

• Explain what causes chain reaction in a nuclear reactor.
• Give one application of radioactivity.
1. The figure below shows the essential component of a X-ray tube.

(i) how are the produced electrons accelerate toward the anode?

(ii) Why is the target made of tungsten?

(iii) How is the cooling achieved in this kind of x-ray machine.

(iv) Why would it be necessary for the target to rotate during operation of this machine?

(v) Why is the machine surrounded by lead shields?

b). If the accelerating voltage is 200Kv. Calculate

1. Kinetic energy of the electron arriving at the target. Take (e=1.6 x10 -19) (2mks)
2. If 0.1% of the electron energy is converted into X rays, determine the minimum             wavelength of the emitted X rays.   (h = 6.63 x 10-34 Js and C = 3.0 x 108m/s)
3. a) The diagram in figure 6 shows an X-ray tube

Figure 6

1. i) Name the parts labeled A, B and C

A……………………………………………………………………

B ……………………………………………………………………

C ……………………………………………………………………

1. ii) Give a reason why B is essential in the X-ray tube

iii)       What features of the operation of the X – ray tube determine;

I           The intensity of the X-ray

II          The quality of the X-rays

1. iv) State two dangers of X-rays
2. b) An accelerating potential of 30KV is applied to an X-ray tube. Calculate;
3. i) The Kinetic energy of the electrons accelerated by this potential
4. ii) The maximum frequency of the X-rays produced by the tube

Take electronic charge e = 1.602 x 10-19C

Planck’s constant h = 6.62 x 10-34Js)

1. a) The diagram below shows part of x-rays tube

 P
 Q
 X-ray

Name parts

P  …………………………………………….

Q ……………………………………………

b)(i) What  is the effect on the wavelength of x-rays if the number of electrons hitting metal target are increased.

(ii) What is the effect on wavelength of x-rays when p.d across the tube is decreased?

1. c) Calculate the maximum velocity of electrons that would produce x-rays of frequency 8.0x 108Hz if only 20% of kinetic energy is converted to x-rays. (Take planks constant = 6.63x 10-35 Js)
2. d) An x-ray tube operating at a potential difference of 50kV has a tube current of 20mA

Calculate

1. i) The electric power input.
2. ii) The number of electrons hitting the target per second.

iii) The velocity of the electrons when they hit the target.

1. Below shows an x-ray tube

1. a) i) Name the elements used in making the parts labeled A and B.

A…………………………………………………………………….

B ……………………………………………………………………

1. ii) Explain the use of the part labeled

iii) Explain how the x-rays are produced.

1. iv) Why is the x-ray tube evacuated?
2. b) The penetrating power of x-rays is normally varied depending on the intended use. Explain briefly how this is done.
3. c) The energy of x-ray is 2.089 x 10-14 Given that the speed of light is 3.0×108m/s and plank’s constant is 6.6 x 10-34Js, find the wavelength of the x-rays.
4. (a) Figure 10 below shows the features of an X-ray tube.

Fig. 10

1. i) Name the parts marked with letters A and B

A…………………………………………………………….

B ………………………………………………………………

1. ii) Explain how a change in the potential across PQ changes the intensity of x-rays produced in the tube.

iii) During the operation of the tube, the target becomes very hot. Explain  how this heat is caused.

1. iv) State the property of lead that makes it suitable for use as shielding material.
2. b) In an certain x-ray tube, the electrons are accelerated by a p.d of 12000V. Assuming all the energy goes to produce x-rays, determine the frequency of the x-rays produced (planks’s constant ,h = 6.62 X 10-34 Js and charge on an electron, e = 1.6 x 10-19c).
3. The fig below shows apparatus used to produce X-rays.

 EHT

1. Name the part marked Aand B

A

B

1. b) Briefly explain how X-rayare produced in the X-ray tube
2. c) An X-ray tube is operating with an anode potential of 5KV and a current of 10 MA.
3. i)    Explain how the intensity of X-rays from such a tubemay be increased
4. ii) Explain how penetrating power of the X-ray in such a tube may be increased

iii)   Calculate the number of electrons hitting the anode per second

1. iv) Determine the velocity with which the electrons strike the target (Take e=1.6×10-19 C and Me=9.1×10-31kg)
2. v) What property of lead makes it suitable for use as shielding material?
3. Figure below shows the structure and circuit of a modern X-ray tube:

(a) (i) Briefly explain how electrons are produced by the cathode.

(ii) How are the electron produced accelerated towards the anode.

(iii) Why is the target made of tungsten?

(iv) How is cooling achieved in this kind of x-ray machine?

(v) Why would it be necessary for the target to rotate during operation of this machine?

(vi) Why is the tube evacuated?

(vii) Why is the machine surrounded by a lead shield?

(b) If the accelerating voltage is 100KV. Calculate:

(i) Kinetic energy of the electrons arriving at the target. (e=1.6×10-19C)

(ii) If 0.5% of the electron energy is converted into x-rays. Determine the minimum wavelength of the emitted x-rays. (h=6.63×10-34J.S and C=3.0×108ms-1)

1. Figure 6 shows the essential components of an x-ray tube.
2. a) i) Explain how electrons are produced by the cathode.
3. ii) State a reason why the cathode is concave shaped.

iii) State two ways in which cooling is achieved in this X-ray machine.

1. b) Explain why:
2. i) It would be necessary for the target to rotate during operation of this machine.
3. ii) The machine should be surrounded by a lead shield.
4. c) If the accelerating potential difference is 100kV, calculate;
5. i) The kinetic energy of the electrons arriving at the target (e=1.6 x 10-19c).
6. ii) The minimum wavelength of the emitted x-rays if 0.5% of the electron energy is converted into x-rays (h = 6.63 x 10-34Js, c = 3.0 x 108m/s).
7. The figure 7 shows the essential component of X-ray tube.

(i)        How are the electrons accelerated towards the anode?

(ii)       Why is the target made of tungsten?

(iii)      How is cooling achieved in this kind of x-ray machine?

(iv)      Why would it be necessary for the target to rotate during operation of this machine?

(v) Why is the machine surrounded by lead shields?

b). If the accelerating voltage is 200KV. Calculate

1. i) Kinetic energy of the electron arriving at the target. Take (e=1.6 x10 -19) (3mks)
2. ii) If 0.1% of the electron energy is converted into X- rays, determine the minimum wavelength of the emitted X-rays. (h = 6.63 x 10-34 Js and C = 3.0 x 108m/s)
3. The figure 11 below shows an X-ray tube

 +  EHT  –

Fig. 11

 A
 B
 Cathode

1. a) (i) Identify the parts labelled A and B

A…………………………………………………

B………………………………………………..

(ii) Which material can be used to make part B? What should be the property of that material?

b)(i) Identify the  process through which electrons leave the filament.

(ii) State one property of lead that makes it useful to be used as a shield to X –rays produced.

1. c) Explain how you can increase the quality of X-rays produced in the tube.
2. The figure below shows an x-ray tube.

Figure 11

1. a) i) Indicate on the diagram the path of the x-ray beam supplied by the tube.
2. ii) Why is B set at an angle of 45º relative to the electron beam?

iii)       Why are cooling fins necessary?

1. iv) Why is the tube evacuated?
2. v) Name the part marked C and state its function.
3. b) An X-ray tube has an accelerating p.d of 100kV. What is the shortest wavelength in its x-ray beam?
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