Physics 1402
Exam No. 3
Physic 1402 Test 3
Name___________________
Instructions: Show ALL work for partial credit.
Multiple Choice:
1.) A 2-T uniform magnetic field makes an angle of 30◦ with the z axis. The magnetic
flux through a 3-m2 portion of the xy plane is:
a.) 2.0Wb
b.) 3.0Wb
c.) 5.2Wb
d.) 6.0Wb
2.) Faraday’s law states that an induced emf is proportional to:
a.) the rate of change of the magnetic field
b.) the rate of change of the electric field
c.) the rate of change of the magnetic flux
d.) the rate of change of the electric flux
3.) In the arrangement shown R = 6 and l = 1.2m. The magnetic field is 2.5 T directed
into the page. At what speed should you move the bar to produce a current of 0.5A in the
resistor?
a.) 1 m/s
b.) 1.3 m/s
c.) 3.1 m/s
d.) 2.58 m/s
4.) A 2 m radius loop is in the Magnetic field shown below. The Magnetic field strength
is reduced from 20 T to 0 T at a steady rate in 5 seconds. If the loop has a resistance of 3
, what current appears in the loop.
a.) 20 Amps Clockwise
b.) 20 Amps Counter clockwise
c.) 16.8 Amps Counter clockwise
d.) 16.8 Amps Clockwise
5.) A Solenoid 2m long has 20 coils and a cross sectional area of 10m2. Find the Self
Inductance of this Solenoid.
a.) 1.81 x 10-4 H
b.) 5 x 10-3H
c.) 2.5 x 10-3H
d.) 3.25 x 10-3H
6.) The operations of an Electric Guitar are primarily examples of
a.) Newton’s Law
b.) Faraday’s Law
c.) Gauss’s Law
d.) Ampere’s Law
7.) An object is placed 2cm from a concave mirror and produces a virtual image that is 3
times as tall as the object. What is the focal length of this mirror?
a.) 3 cm
b.) 66 cm
c.) 0.33 cm
d.) –3 cm
8.) A beam of light is incident from air on the surface of an unknown liquid. When the
angle of incidence is 30o it is found that the angle of refraction is 22o. Find the critical
angle for the liquid when surrounded by air.
a.) 48.5o
b.) 56.8o
c.) 36.5o
d.) 35.6o
9.) An object 3 m tall is placed 2 m from a convex lens with focal length f = 0.5 m.
How tall is the image?
a.) 0.5 m
b.) 2 m
c.) 3 m
d.) 1 m
10.) A source of light is 5m below the surface. All light that emerges from the water
does so through a circle due to total internal reflection. Find the radius of this circle. nw =
1.3
a.) 4.3m
b.) 8.5m
c.) 6.02m
d.) 5m
Short Answer/Drawing:
11.) An object is placed a distance 2f from a covex lens. Use a ray-tracing diagram to
determine to find the approximate location of the image and to determine if it is real or
virtual, and up-right or reversed.
12.) Use Lent’s Law to find the current directions in each of the loops below as the
current near the loop INCREASES.
Show All Work:
13) A rod with resistance R lies across frictionless conducting rails in a constant uniform
magnetic field B, as shown. Assume the rails have negligible resistance. The magnitude
of the force that must be applied by a person to pull the rod to the right at constant speed
v is:
14.) A 1.6m person stands 2.4m away from a mirrored globe of 0.18m diameter. How
large is the image of the person seen in the globe.
15.) When you stand with a flat mirror 1m behind you and another flat mirror 4m in
front of you, you see an infinite series of images both in front of you and behind you.
This is caused by the flat mirrors first reflecting you and then the mirrors reflect the
images of you and then reflecting the images of the images and so on..
Find the locations of the first two images that you see in front of you on the scale given.