Cambridge International AS and A Level Physics Coursebook 2nd. Edition by David Sang, Graham Jones, Gurinder Chadha, Richard Woodside | 9781107697690 | 1107697697 | Holooly

Cambridge International AS and A Level Physics Coursebook

659 SOLVED PROBLEMS

Question: P2.WE.1

Plan an experiment to measure the resistivity ρ of glass, which is about 10^10 Ω m. You have available a number of sheets of glass of the same size but different thicknesses. Resistivity ρ is defined as ρ = RA/l ...

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Step 1 Identify the variables.The independent vari...

Question: 32.WE.2

A beam of ultrasound is normally incident on the boundary between muscle and bone. Use Table 32.3 to determine the fraction of its intensity which is reflected. ...

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Step 1 Write down the values of

Z_{1}[/late...

Question: 32.11

Quartz is an example of a piezo-electric material. The speed of sound in quartz is 5700 m s^−1. a Calculate the wavelength of ultrasound waves of frequency 2.1 MHz in a quartz crystal. b If the crystal is to be used in an ultrasound transducer, its thickness must be half a wavelength. Calculate the ...

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a Rearrange speed v = fλ to give wavelength [latex...

Question: 32.7

The data in Table 32.2 shows how the attenuation coefficient μ depends on the energy of the X-rays in bone and muscle. When making a diagnostic X-ray image, it is desirable that bone should be clearly distinguished from muscle. Use the data in Table 32.2 to explain why it would be best to use lower ...

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Consider the ratio of attenuation coefficients bon...

Question: 32.2

Determine the minimum wavelength of X-rays emitted from an X-ray tube operated at a voltage of 120 kV. ...

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Photon energy

E = \frac{hc}{λ} = V × e[/lat...

Question: 32.WE.1

The attenuation (absorption) coefficient of bone is 600 m^−1 for X-rays of energy 20 keV. A beam of such X-rays has an intensity of 20 Wm^−2. Calculate the intensity of the beam after passing through a 4.0 mm thickness of bone ...

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Step 1 Write down the quantities that you are give...

Question: 31.20

The isotope 7^16 N decays with a half-life of 7.4 s. a Calculate the decay constant for this nuclide. b A sample of 7^16 N initially contains 5000 nuclei. Determine how many will remain after a time of: i 14.8 s ii 20.0 s ...

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a Decay constant

λ = \frac{0.693}{7.4} = 0....

Question: 3.12

If you drop a large stone and a small stone from the top of a tall building, which one will reach the ground first? Explain your answer. ...

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The large one; its weight is greater, so it reache...

Question: 2.25

A stone is thrown with a velocity of 8 ms^−1 into the air at an angle of 40° to the horizontal. a Calculate the vertical component of the velocity. b State the value of the vertical component of the velocity when the stone reaches its highest point. Ignore air resistance c Use your answers to a and ...

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a Vertical component of velocity

= 8 \times...

Question: 20.16

A signal of 1.0 mW passes through an amplifier of gain 30 dB and then along a cable where the attenuation is 18 dB. a What is the overall gain of the signal in dB? b What is the output power at the end of the cable? ...

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a Given that gain and attenuation expressed in dec...

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