Physics 1310 Make-Up Exam Name: key
1. A biology student doing field work is using an insulated container with dimensions equal to 20 cm x
20 cm x 20 cm. (The total surface area of the exterior container walls equals 0.24 m2.) The thickness of
the container walls equals 3.6 cm. The thermal conductivity of the container material equals
0.030 W/mK. The temperature outside the container equals 25°C and the temperature inside the
container equals 0C. The flow of heat into the container equals:
b. 5.0 W
2. The three particles shown to the right have the following charges:
q1 = - 5.0 x10-6 C, q2 = +1.0 x10-6 C, and q3 = + 5.0 x10-6 C.
In this diagram d = 1.5 cm. The magnitude of the electric field that q1 and
q3 produce at the location of q2 equals:
e. 4.0 x108 N/C
3. The three particles shown to the right have the following charges:
q1 = - 5.0 x10-6 C, q2 = +1.0 x10-6 C, and q3 = + 5.0 x10-6 C.
In this diagram d = 1.5 cm. The magnitude of the net force that q1 and q3
exert on q2 equals
e. 400 N
4. Starting from rest a proton (q = +1.6x10-19 C and m = 1.67x10-27 kg) is accelerated by a uniform
electric field between the two plates of a particle accelerator. The plates are separated by 2.0 cm. The
proton begins at the positive plate and goes to the negative plate. When the proton reaches the negative
plate, its kinetic energy equals 10,000 eV. The electrical potential difference between the two plates of
the accelerator equals
e. 10,000 V
5. A long straight wire carries a current equal to 50
A. A 5.0 cm long short wire segment that carries a
current of 30 A is suspended 2.0 cm above the long
straight wire by the magnetic force that the long
wire exerts on the short wire segment.
5.0 cm
30 A
2.0 cm
The mass of the short wire segment equals
50 A
b. 0.077g
1.
6. Consider the simple DC circuit illustrated to the right. The battery EMF
equals 12.0 volts and the resistance of the resistor, R, equals 6.0 ohms. The
power dissipated in the resistor equals:
d. 24 Watts
7. A wire is 2.0 meters long and has a radius equal to 0.32 mm. The measured resistance of this wire
equals 0.10 ohms. The resistivity of the wire equals:
a. 1.6x10-8 ohm-m
8. A pulsed laser beam has an intensity equal to 1.33x109 W/m2. The amplitude of the E field
associated with this wave equals
e. 1.0x106 N/C
9. As shown in the sketch, a rectangular wire loop
moves with a speed equal to 50 m/s toward the right.
The right end of the loop is in a uniform and constant
magnetic field that is perpendicular to the loop. The
electrical resistance of the loop equals 2.0 ohms. The
current induced in the loop equals 2.5 A. The magnitude
of the B field equals
b. 0.50 T
10. As shown to the right, a light ray is incident on
the plastic-water interface. If the ray is totally
internally reflected, then
glass
d.  must be greater or equal to 62.5 .
n = 1.50
water

n = 1.33
11. The image formed by the converging lens in the diagram below is
Object
F‘
F
c. upright
12. If white light is incident on a diffraction grating, then in the visible part of the spectrum produced by
this device,
b. red light appears at the largest diffraction angle.
2.
13. A physics student uses a camera with a 50 mm focal length to photograph a tree that is 10 m high
and is located 100 m from the lens. The camera forms a real image of this object. The size of the image
is approximately equal to:
a. 5.0 mm
14. A telescope has an objective lens with diameter equal to 20 cm and focal length equal to 2.0 m. The
telescope is being used to view Jupiter that has an angular size equal to 0.10 mrad. What is the angular
size of the image of Jupiter formed by this instrument when it is used with an eyepiece that has a 50 mm
focal length?
c. 4.0 mrad
15. An amateur astronomer is photographing double stars using a telescope with a 10 cm diameter. The
color of the stars corresponds to 500 nm. If the angular distance between two stars equals 8.0 x10-6
radians, then
a. the stars will be resolved as two distinct star images.
16. A converging lens with a 5.0 cm focal length is being used as a magnifying glass. A student is
looking at a flower component that has an angular size equal 3.0 mrad when viewed by naked eye. What
is the angular size of this same object when viewed with this magnifying glass?
d. 15 mrad
17. Unpolarized light with intensity equal to 400 W/m2 is incident on an ideal polarizer that
has its transmission axis oriented vertically. Light that passes through this polarizer then
passes through an ideal polarizer with its transmission axis rotated 30 degrees up from the
horizontal. The intensity of the light that passes through the second polarizer equals:
c. 150 W/m2
18. The power emitted by a UV laser with a wavelength of 310 nm is 6.4 W. The rate of photon
flow out of this laser (number of photons/s) is about:
e. 1 x1019 photons/s
19. The wavelength of the hydrogen emission line corresponding to the n = 8 to n = 2 transition equals
b. 389 nm
20. Monochromatic light with wavelength 560 nm in air is traveling through air. It
is incident on a lens (n lens = 1.35) that is coated with a thin film (n film = 1.40).
There is no reflection of this light from the coated surface. The thickness of the thin
film is somewhere between 350 and 500 nanometers. The thickness of the thin film
coating equals:
b. 400 nm
3.