PHYS*1070

INTRODUCTORY PHYSICS FOR THE LIFE SCIENCES I

SAMPLE FINAL EXAMINATION 1

N O T E: NOT ALL QUESTIONS MAY BE APPLICABLE IN CURRENT SEMESTER;

CLICK ON CORRECT ANSWER FOR SOLUTION

1. A traveling sound wave has a speed in air of 340 m s^{-1}
and a wavelength of 0.50 m. Which equation below could describe this wave?

(A) y = -y_{0} sin (1360 pt
+ 4px)

(B) y = 2y_{0} cos (340 pt) sin (0.50
px)

(C) y = y_{0} sin (680 t - 0.50 x)

(D) y = y_{0} cos (1360 pt) sin (4px)

(E) y = y_{0} sin (340 pt - 0.50px)

2.A standing wave is described by the equation:

y = -20.0 cos (3.00 t) sin (8.00 x)

when x and y are in cm and t is in seconds. At what time will the shape
of this wave be perfectly flat i.e. the reflected wave will cancel the
incident wave everywhere where the equation is valid.

(A) 0.370 s

(B) 0.524 s

(C) 0.631 s

(D) 0.823 s

(E) 0.967 s

3.Below are four statements ((i) - (iv)) concerning the human ear:

(i) The tympanic membrane, oscicles and oval window form a piston-lever
system which amplifies the pressure fluctuations in the sound wave.

(ii) The average human ear is most sensitive to sounds of frequency
about 3500 Hz; at this frequency the average human can just hear sounds
of intensity about 1 x 10^{-12} W/m^{2}.

(iii) The basilar membrane contains the hair cells which change mechanical
oscillations to electrical nerve signals.

(iv) The region of maximum oscillation of the basilar membrane depends
on the sound frequency; this may be one way we recognize sounds of different
pitch.

Which of the above statements is/are correct?

(A) All of the above statements are correct.

(B) Statements (i) and (iii) are correct; the rest are false.

(C) Statements (ii) and (iv) are correct; the rest are false.

(D) Statements (i), (ii) and (iv) are correct; (iii) is false.

(E) None of the statements is correct.

4.Cloud-to-cloud lightning produces thunder which can be heard by observers
on the ground below. One particularly brilliant flash produced a loud thunder
crash for 200 ms (1 ms = 10^{-3} s). The sound of the thunder reached
the ear of an observer 4.0 s after the flash was seen. The intensity level
of the thunder measured by the observer was 92 db. What acoustical energy
(in J) was released when the thunder was produced? (I_{0} = 1.0
x 10^{-12} W m ^{-2})

(A) 7.4 x 10^{3}

(B) 29

(C) 1.6 x 10^{5}

(D) 6.7 x 10^{-6}

(E) 0.20

5.

In the acoustics experiment an audio oscillator (A) drove a small speaker
(S) located at the mouth of a tube containing a moveable piston P. In one
experiment, "loud sound" was heard when the piston was at the four locations
indicated by the four vertical arrows. The distances (5.2 cm and 36.4 cm)were
measured from the speaker end of the tube to the first and fourth piston
position, as indicated.
The frequency of the sound was: (answers are to 3 significant figures) |

(A) 980 Hz

(B) 1210 Hz

(C) 1420 Hz

(D) 1640 Hz

(E) 3120 Hz

6.Which ray diagram below, for a single, spherical refracting surface,
illustrates the concepts of both a **virtual object and virtual image**.
The solid straight lines represent light rays.

(A)

(B)

(C)

(D)

(E)

7.

A goldfish (F) is floating in a spherical bowl of radius 20 cm. The
bowl is filled with water (n = 1.33) and the fish is 6.0 cm to the right
of the center (C) of the bowl, as shown. Which row below describes the
fish as seen by a viewer (eye at X) 1.0 m to the right of the bowl? (Answers
to
2 significant figures.) |

- | Location of image | Size of image relative to actual fish |

A | 7.3 cm to right of centre | 14% larger |

B | 7.3 cm to right of centre | 21% larger |

C | 6.2 cm to right of centre | 11% larger |

D | 6.2 cm to left of centre | 12% larger |

E | 13 cm to left of centre | same size |

8. A person has his eyesight corrected to the standard 25 cm nearpoint
with a lens of +2.6 diopters Where is his nearpoint without the correcting
eyeglasses?

(A) 0.18 m

(B) 0.27 m

(C) 0.45 m

(D) 0.63 m

(E) 0.71 m

9.

The diagrams represent "images" (diffraction patterns) on the retina corresponding to 2 point objects of different angular separation. Recall that each image or diffraction pattern consists primarily of a bright central disk surrounded by a minimum (dark ring) which is surrounded by a weak. maximum (a weak bright ring). In these diagrams the dark areas correspond to bright areas in the patterns. Which diagram represents the 'Rayleigh Criterion' for resolution of the two images? |

(A) (Diffraction patterns well separated)

(B) (Weak bright rings coincide)

(C) (Minima or dark rings coincide)

(D) (Minima of one pattern coincides with center
of the other)

(E) (Central disks overlap 80% by area)

10. The butadiene molecule is illustrated below. (C-C bond length =
0.15 nm; 1 nm = 10^{-9}m)

What is the probability of finding an n = 2 p-electron in a region of length 0.0030 nm, centered half-way between carbon 1 and carbon 2? You may assume that the probability density is constant in this 0.0030 nm interval.

(A) 0.010

(B) 0.020

(C) 0.030

(D) 0.200

(E) 1.00

11.

The diagram (right) shows the p-electron
energy levels of a linear molecule with 4 elec~ons in a possible arrangement.
A photon of wavelength 568 nm is incident on the molecule. Which diagram
A to D below illustrates the new electron arrangement if the photon is
absorbed (assume that it is absorbed if absorption is possible). If it
is not possible for this photon to be absorbed by this molecule, select
answer E (1 nm = 10^{-9} m). |

(A)

(B)

(C)

(D)

(E) This photon cannot be absorbed by this molecule.

12. A **circular** carbon-chain molecule contains 10 carbon atoms;
the C-C bond length is 0.15 nm. What photon energy is required to raise
this molecule from its electronic ground state to its first excited state.
(1 nm = 10^{-9} m)

(A) 2.1X10^{-19} J

(B) 3.0X10^{-19} J

(C) 3.7X10^{-19} J

(D) 4.5X10^{-19} J

(E) 5.4X10^{-19} J

13. A molecule can absorb radiation of wavelengths: 4.0 x 10-3m, 4.0
x 10^{-6} m and 4.0 x 10^{-7} m. Choose the two that correspond
to an electronic transition and a pure rotational transition and determine
the ratio of the photon energy for the electronic transition to that for
the pure rotational transition. The ratio is:

(A) 10^{4}:1

(B) 10^{3}:1

(C) 1^{2}: 1

(D) 20:1

(E) 5:1

14.

The diagram, illustrates molecular energy levels as discussed in this course. Below are 5 statements ((i) - (v)) concerning this diagram: |

(i) Arrow 1 represents absorption of light.

(ii) Arrows 2 represent energy going into heat.

(iii) Arrow 3 represents fluorescence.

(iv) Arrow 4 represents a 'spin flip'.

(v) Arrow 5 represents phosphorescence

Which of the above statements is/are correct?

(A) All are correct.

(B) (i),(ii) and (v) are correct; the rest are false.

(C) (i), (iii) and (v) are correct; the rest are false.

(D) (iii),(iv) and (v) are correct; the rest are false.

(E) None is correct.

15.

The graph shows the variation of extinction coefficient e
(dm^{3}/mole cm) with wavelength l (nm)
for a sample of water from a local pond. The absorbance of this water at
l
= 400 nm as measured in a 1.00 cm cuvette is 0.030. W hat will be the %
T at 600 nm for a 50.0-cm-long sample of this water? |

(A) 0.13 %

(B) 0.56%

(C) 1.3 %

(D) 2.8%

(E) 6.8 %

16. The graph below shows a computer simulation of the count rate for absorption of ,g -ray photons by lead, as a function of the thickness of lead. Note that the best fitting straight line passes through the points (0, 3600) and (0.5, 1950). From this graph, what is the linear attenuation coefficient of lead?

(A) 5.0 cm^{-1}

(B) 4.3 cm^{-1}

(C) 3.5 cm^{-1}

(D) 2.7 cm ^{-1}

(E) 1.2 cm^{-1}

17. Ingested ^{131}I has been used medically to treat diseased
thyroid tissue. One day a radiation detector placed near a patient's thyroid
reads 10^{3} counts/s. Forty-eight hours later it reads 560 counts/s.
What is the biological halflife of ^{131}I in the thyroid? (The
physical halflife of ^{131}I is 8.1 days.)

(A) 1.7 days

(B) 2.6 days

(C) 3.4 days

(D) 6.8 days

(E) 9.3 days

18.

A zoologist conducting experiments on marine larvae, uses an aquarium
containing artificial sea water (salt solution). He needs to know the electrical
conductance of the salt solution. He places two metal electrodes in the
aquarium as shown and connects them through an ammeter (A) to a 12.0 volt
battery. The symbol G_{s} represents the conductance of the solution.
The symbol Gc = 1.0 S represents the conductance of the rest of the circuit.
If the ammeter (A) reads 0.50 A, what is the value of the solution conductance
Gs? |

(A) 0.013 S

(B) 0.027 S

(C) 0.036 S

(D) 0.043 S

(E) 0.068 S

19.

Due to nearby charges, the point P has the electrical properties shown,
i.e. the electric field is 3000 N/C to the right and the electrical potential
is -200 V (relative to V = 0 at infinity).
If an electron (e = 1.60 x 10 |

(A) The electrical force on the electron is 4.8 x 10^{-16} N
to the left.

(B) The electrical potential energy of the electron is +3.2 x ^{-17}
J (relative to zero at infinity).

(C) The work done against the electrical field to move the electron
from infinity to point P was +3.2 x 10^{-17}J.

(D) If the electron at P is released and the electric field accelerates
it back to infinity without collisions (ie in a vacuum) the electron's
kinetic energy at infinity will be +3.2 x 10^{-17}J.

(E) If all of statements A to D are correct,
select E.

20.

The diagram shows a battery (terminal voltage V) connected by copper wires (of very large conductance) to a tube containing NaCI solution of conductivity s. The tube has a length L and uniform cross-sectional area A. Suppose V, A, L and s are varied (one at a time) and I is measured for each arrangement. Graphs of I vs V, A, L and s are plotted. Which graph (A to D) below is NOT correct. If all are correct, select answer E. |

(A)

(B)

(C)

(D)

(E) All of the above graphs are correct