F2

I - MCQ’s

1.      Doubling the component of the applied force  F1 perpendicular to the wrench as shown without changing the component F2 parallel to the wrench;

a) Halves the torque arm                                      b) Doesn't change the torque

c) Doubles the magnitude of the torque             d) Quadruples the magnitude of the torque

2.       A seesaw is supported by a fulcrum as shown. A 40 kg boy sits at the left, 4 meter away from the fulcrum. A girl sits at the right, 5meter from the fulcrum. If the seesaw is balanced, what is the girl's mass?

a) 23 kg                      b) 32kg                  c) 23N                    d) 32 N

3.      When you multiply the normal force times the distance, you can find which of the following;

a) Power                   b) Mechanical advantage

c) torque                   d) Center of gravity

4.      At  given temperature, the resistance of a wire to direct current depends only on,

a) Voltage applied across the wire

b) Resistivity, length, and voltage

c) Voltage, length and cross-sectional area

d) Resistivity, length and cross sectional area

5.The membrane capacitance of a myelinated axon of radius 5mm and length 2cm is ;

( Cm= 5x10-5 Fm-2)

a) 4.13 x10-3 F             b) 3.14x10-11F                   c) 6.28x10-7 F      d) 4.9x10-15 F

6.      In resting state of an axon, the number of a certain ion is 1.2x1026 ions inside the cell. The concentration of that ion in 1m3 of that axon is;

(Avogadro's number = 6.02x1023 ion/mole)

a) 200 moles/m3          b) 100 moles/m3         c) 1.2                 d) 7.22x1049

7.                  In Nernest equation, the equilibrium potential occurs when;

a) The flow due to potential difference is equivalent to the flow due to permeability

b) The potential energy of a certain ion equals the energy required for diffusion of that ion

c) The number of ions inside and outside the cell is the same

d) The active transport is maximum

8.      The threshold of the weak stimulus is ;

a) equal to -50 mV                            b) equal to 50mV

c) less than -50mV                            d) greater than 50 mV

9.      The speed of propagation in an myelinated nerve with radius 4µm is ;

a) 0.04 m/s                    b) 40 m/s              c) 4 m/s                 d) 0.4 mm/s

10.  The activity of a radioactive sample (with a single radioactive nuclide), decrease to its initial value in a time interval of 96 days. What is the half- life of the radioactive nuclei present

a) 6days                       b) 8 days                         c) 12days                     d) 32days

11.  Some types of cancer can be effectively treated by bombarding the cancer cell with high energy photons. If a patient received 1000 rads of these photons which has quality factor of 0.6, the biological equivalent dose he received is;

a) 600 seivert            b) 60 gray               c) 6 seivert             d) 0.006 gray

12.  Which is true:

a) Alpha particle is an electromagnetic radiation

b) Gamma ray is an electron with negative charge

c) Gamma rays initiate when an electron drop from higher energy orbits to lower one

d) Beta particle is an electron with positive charge or negative charge

13.  The frequency of the Compton scattered radiation is-------------- the frequency of the incoming x-ray photon;

a)      smaller            b) the same as        c) larger               d) not related to

14.  The characteristic sharp lines of the x-ray spectrum always result from;

a)            The transition of the inner shell electrons

b)            The electron energy levels that have the same electron number

c)            The emission of beta particles from the nucleus

d)           The neutrons within the nucleus

e)            The protons within the nucleus

15.  The pressure below a column of liquid does not depend on:

a)      The acceleration of gravity.

b)      The density of the liquid.

c)      The height of the liquid.

d)     The area of the liquid surface

16.  Blood in 0.2 m long segment of an artery moves at an average velocity of 0.03 m/s. The pressure drop in the segment is 5 Pa and its radius is 0.002 m. The power, in W, expended to maintain the flow is:

a) 18.8x10-6                 b) 1.88x10-6                       c) 0.188x106        d) 1885

17.  What is the difference in pressure between the brain and foot of 1 m child, if the density of blood is 1059.5 kg m-3.

a) 103 Pa                      b) 108 Pa         c) 1.04x104 Pa             d) 9.3x10-3Pa

18.  A flute is played with a fundamental harmonic of 196 Hz (two open ends). The length of the air column is 89.2 cm. The speed of the wave resonating in the flute is

a) 699.3m/s      b) 340m/s         c)349.6m/s       d)34966m/s

19.  A sound has an intensity of 5.0 x 10-7 W/m2. The intensity level is

a) 56.99 W/m2             b) 57 dB          c) 5.69 dB                    d) 67 dB

20.  An ultrasound wave of intensity Ii travels in water whose density is 1000 kg m-3. While passing into another medium some is reflected back so that the reflected intensity IR is 0.0064 Ii ; then the medium density in kg m-3  is:

a) 852                               b) 987                          c) 994                          d) 1110

21.  Light is incident in glass on air-glass boundary, what is the critical angle  if the refractive index of air is 1and the refractive index of glass is 1.7?

a) 36o              b) 0.19 rad                   c) 74.6º                        d) 90º

22.  An object is placed 18 cm in front of a converging lens with focal length 36 cm. Which of the following correctly characterizes the resulting image?

a)      real, erect, and larger than the object

b)      real, inverted, and smaller than the object

c)      virtual, erect, and larger than the object

d)     virtual, inverted, and smaller than the object

23.  The furthest object a particular nearsighted person can see clearly is 1 m away. In order to correct for this, this person wears glasses. What kind of lenses should he wear?

a) Converging lens with f = 1 m

b) Diverging lens with f = 1 m

c) Converging lens with f = 1.1 m

d) Diverging lens with f = 1.1 m

24.  A lens with a power of 4 Δ is combined with a lens of 1 Δ. The power of the system is

a) 3 Δ               b) 0.2 watts                  c) 5 Δ               d) 0.25 j/s

25.  The internal energy of 7100 kJ is obtained by metabolism of body fat. How many grams of fat are used up if the energy content per unit mass of fat is 38.9 x103 J/g?

a) 183                          b) 276190                    c) 5.48                         d) 71

26.  The energy content per unit mass is defined as:

a) The product of the Oxygen consumed and the energy released.

b) The ratio of the energy released to the mass consumed.

c) The mass used per unit volume of Oxygen.

d) The ratio of the oxygen consumed to the energy released.

II - PROBLEMS

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1-      A shop sign weighing W = 231 N is supported by a uniform beam of

weight 137 N supported by a cable 1.24m from the backboard as shown

a) Find the tension in the cable if it forms an angle of 38o to the beam

1m

b) Find the horizontal force exerted to the beam from the hinge.

W=231 N

2-            The equilibrium potential at 37oC for Cl- ions in a particular axon is -85mV. If the Cl- concentration outside the cell is 110 moles m-3, what is the concentration inside the cell

3-   A 60 kg patient about to have a brain scan is injected with 20 mCi of technetium- 99 (T = 6 hrs ) which emits 143 keV photons. Assuming that half of these photons escapes the body without interacting, what biological equivalent dose the patient receives? (Quality factor (QF) of these photons is 0.9).

4 -a) Describe the photoelectric effect as a photon interacted with matter, showing the energy range it occurs (you can use drawings )

5.      Blood passes through 1mm long capillary in the circulatory system. If the radius of the capillary is 7x10-6 m, the pressure drop is 2.6 x103 Pa, and the viscosity of blood is 2.084X10-3 Pa s find:

a)      The flow rate of blood.

b)      The power expended against viscous forces.

6.      The length of the auditory canal in humans averages about 2.5 cm. What are the lowest three standing-wave frequencies for a pipe of this length open at one end? (velocity of sound 340 m/s)

7.      A system of two lenses has a focal distance of -100 cm. One of the lenses has power of 2 Δ. What is the focal distance of the other?

8.   A 70 kg man swims with an efficiency of 10% and his metabolic rate is 11 W kg-1.His basal metabolic rate is 1.2 W/kg.

a) What is his power output?

b) How much work does he do in one hour?