UNIVERSITY OF GUELPH

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 = -y0 sin (1360 pt + 4px)

(B) y = 2y0 cos (340 pt) sin (0.50 px)

(C) y = y0 sin (680 t - 0.50 x)

(D) y = y0 cos (1360 pt) sin (4px)

(E) y = y0 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/m2.

(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? (I0 = 1.0 x 10-12 W m -2)

(A) 7.4 x 103

(B) 29

(C) 1.6 x 105

(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 = 10-9m) 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) 104:1

(B) 103:1

(C) 12: 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 (dm3/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 131I has been used medically to treat diseased thyroid tissue. One day a radiation detector placed near a patient's thyroid reads 103 counts/s. Forty-eight hours later it reads 560 counts/s. What is the biological halflife of 131I in the thyroid? (The physical halflife of 131I 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 Gs 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 10-19 C) is located at point P, which one, if any, of the statements A to D is NOT correct. If all statements A to D are correct, select answer E. (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 10-17J.

(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 10-17J.

(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