Download Exam review Notes - University of Toronto Physics

Clicker Question 1:
Which is an inertial reference frame (or at least
a very good approximation of one)?
A. A jet plane during takeoff.
B. A jet plane flying straight and level at
constant speed.
C. A jet plane turning at constant speed.
D. B and C.
E. A, B, and C.
Physics 202: Lecture 8, Pg 2
Clicker Question 2:
A spaceship travels at a constant speed to a
distant planet. If the trip takes 12 yrs
according
di tto clocks
l k on th
the earth,
th and
d9
9.2
2
years according to clocks on the ship, how far
awayy is the planet
p
((in the Earth frame)?
)
(a)
(b)
(c)
(d)
(e)
6.34
6
34 lightyears
8.95 lightyears
7.68 lightyears
11 45 lightyears
11.45
li ht
12 lightyears
Physics 202: Lecture 8, Pg 3
Clicker Question 2:
A spaceship travels at a constant speed to a distant
planet If the trip takes 12 yrs according to clocks on
planet.
the earth, and 9.2 years according to clocks on the
ship,
p how far away
y is the p
planet?
Physics 202: Lecture 8, Pg 4
Physics 202: Lecture 8, Pg 5
Clicker Question 3:
A firecracker explodes high overhead. You notice a
slight delay between seeing the flash and hearing the
b
boom.
At what
h t time
ti
does
d
th
the eventt “firecracker
“fi
k
explodes” occur in your reference frame?
A. At the instant you hear the boom.
B At the instant you see the flash.
B.
flash
C. Very slightly before you see the flash.
D Very
D.
V
slightly
li htl after
ft you see th
the flflash.
h
E. There’s no unique answer because it depends on
the observer.
observer
Physics 202: Lecture 8, Pg 6
Clicker Question 4:
Peggy passes Ryan at velocity v. Peggy and Ryan
both measure the time it takes the railroad car, from
one end to the other,
other to pass Ryan.
Ryan The time interval
Peggy measures is ____ the time interval Ryan
measures.
A. longer than
B. at the same as
C. shorter than
Physics 202: Lecture 8, Pg 7
Clicker Question 5:
A nuclear bomb releases roughly 5  1014 J when it
explodes. About how much mass is lost during the
explosion?
(a)
(b)
(c)
(d)
(e)
5.6 grams
5.6 kg
560 kg
5
5.6
6  106 kg
5.6  1010 kg
Physics 202: Lecture 8, Pg 8
Clicker Question 6:

A circular loop of radius r = 5 cm and resistance R =
0 10 Ω is in a region where there is a uniform
0.10
magnetic field in the direction shown in the figure
that increases linearly with time according to the
expression B(t) = B0 t / τ with B0 = 0.5
0 5 T and t = 100
s. (The loop is stationary.)
What direction will
current flow in the loop?
(a)
(b)
Physics 202: Lecture 8, Pg 9
Clicker Question 7:
A circular loop of radius r = 5 cm and resistance R =
0.10 Ω is in a region
g
where there is a uniform
magnetic field in the direction shown in the figure
that increases linearly with time according to the
expression
p
B(t)
( ) = B0 t / τ with B0 = 0.5 T and τ =
100 s. (The loop is stationary.)
What is the magnitude
of the induced current in
the loop?
(a)
(b)
(c)
(d)
(e)
I=0
I = 0.34 mA
I = 0.39 mA
I = 0.2
0 2 mA
I = 3.4A
Physics 202: Lecture 10, Pg 10
Clicker Question 7:
A circular loop of radius r = 5 cm and resistance R = 0.10 Ω is in a
region where there is a uniform magnetic field in the direction
shown in the figure that increases linearly with time according
to the expression B(t) = B0 t / τ with B0 = 0.5 T and τ = 100 s.
(The loop is stationary.)
What is the magnitude of the induced current in the loop?
Physics 202: Lecture 10, Pg 11
Clicker Question 8:
A conducting metal band containing a 5 Ω resistor is
formed into a circle of radius R as shown in the
diagram. The computer-controlled screw drive turns
so as to decrease the circumference of the loop.
Because of this a current flows:
(a) CW
(b) CCW
Physics 202: Lecture 8, Pg 12
Clicker Question 9:
What is the sign of q?
(a) positive
(b) negative
(c) need more information
Physics 202: Lecture 8, Pg 13
Clicker Question 10:
What is the magnitude of the current I2? Assume R1
= 1, R2 = 2, R3 = 3, 1 = 15 V and 2 = 9 V.
a)
b)
c)
d)
e)
200 mA
500 mA
1A
2A
3A
Physics 202: Lecture 8, Pg 14
Clicker Question 10:
What is the magnitude of the current I2? Assume R1 = 1, R2 =
2 R3 = 3,
2,
3 1 = 15 V and
d 2 = 9 V
V.
Physics 202: Lecture 8, Pg 15
Clicker Question 11:
As in lecture
lecture, a cylindrical magnet is released to fall
through a narrow copper pipe. Assume, as shown,
that it is dropped with the north pole closer to the
ground The tube is at rest.
ground.
rest An induced current
flows in the direction indicated by the arrow
(T) True
(F) False
Physics 202: Lecture 8, Pg 16
Clicker Question 12:
What is the magnitude of the magnetic force acting on a 1.5 m
segment of wire #1 due to the current in wire #2?
(a) 6 × 10-9 N
(b) 7.5 × 10-9 N
(c) 9.75 × 10-9 N
(d) 2 × 10-9 N
(e) 4 × 10-9 N
Physics 202: Lecture 8, Pg 17
Clicker Question 13:
A triangular
g
loop
p carries a current I = 12 A. A magnetic
g
field is
present, B = 0.2 T. The loop lies in the x-y plane and the
magnetic field B points in the x direction. What is the magnetic
force F3 acting
g on the left side of the loop,
p, the hypotenuse
yp
of the
triangular loop?
(a) F3 = 0 N
(b) F3 = 1.8
18N
(c) F3 = 2.5 N.
(d) F3 = 3.2 N
(e) F3 = 4.0
40N
N.
Physics 202: Lecture 8, Pg 18
Clicker Question 14:
A charged particle is traveling at speed vv. It
encounters a static magnetic field oriented
perpendicular to its path. The particle changes its
(a)
(b)
(c)
(d)
(e)
speed ( = magnitude of the velocity).
direction.
direction
both its speed and direction.
neither its speed or direction
direction.
All of the above scenarios are possible.
Physics 202: Lecture 8, Pg 19
Clicker Question 15:
The trajectory of the particle is best described as
(a) a helix.
(b) a circle oriented in the plane of the page
page.
(c) a circle oriented perpendicular to the page.
Physics 202: Lecture 8, Pg 20
Clicker Question 16:
Two particles with equal but opposite charge are
emitted back-to-back at the same speed from the
g
below. Their trajectories
j
lie in
center of the diagram
a plane normal to the magnetic field that points into
the page. The signs of the particles (positive or
g
) are indicated by
y the "+" or "-" at the ends
negative)
of the arrows. Which picture below could be
correct?
Physics 202: Lecture 8, Pg 21
Clicker Question 17:
Three particles of the same charge and the same
speed of v,
v but with three different masses
masses, enter a
region of constant magnetic field into the page (B =
0.5 T) A uniform electric field is now applied in the
region of the magnetic field so that particles continue
to move up vertically without bending. What should be
the direction of this electric field?
(a)
(b)
(c)
(d)
(e)
right
left
up
down
into the page
Physics 202: Lecture 8, Pg 22
Clicker Question 18:
A long wire carries current (I = 0.5 A as shown). An
electron
l
iis moving
i at the
h speed
d off 2000 m/s
/ at a
distance 10 cm from the current carrying wire,
making an angle of 45° relative to the wire. The
19
magnitude of the electron's charge is |q|=1.6 × 10-19
C and its mass is 9.1 × 10-31 kg.
What is the magnitude of the magnetic force on the
electron?
(a) 2.3 × 10-22 N
22 N
(b) 3
3.2
2 × 10-22
(c) 5.1 × 10-22 N
(d) 6.5 × 10-22 N
(e) 8
8.4
4 × 10-22 N
Physics 202: Lecture 8, Pg 23
Clicker Question 18:
A long wire carries current (I = 0.5 A as shown). An electron is
moving
i att the
th speed
d off 2000 m/s
/ att a distance
di t
10 cm from
f
the
th
current carrying wire, making an angle of 45° relative to the
wire. The magnitude of the electron's charge is |q|=1.6 × 10-19 C
31 kg.
and
d itits mass iis 9
9.1
1 × 10-31
k What
Wh t is
i the
th magnitude
it d off the
th
magnetic force on the electron?
Physics 202: Lecture 8, Pg 24
Clicker Question 19:
A rectangular current loop is located near a long, straight wire
that carries a current of 8 A flowing to the right (see the figure).
The current in the loop Iloop = 30 A is flowing clockwise. The
magnitude of the net force on the entire loop is
(a)
(b)
(c)
(d)
(e)
|F| = 4.2 × 10-5 N
|F| = 8.4 × 10-5 N
|F| = 12.6 × 10-5 N
|F| = 14.5
14 5 × 10-5 N
|F| = 16.8 × 10-5 N
Physics 202: Lecture 8, Pg 25
Clicker Question 19:
A rectangular current loop is located near a long, straight wire
that carries a current of 8 A flowing to the right (see the figure).
The current in the loop Iloop = 30 A is flowing clockwise. The
magnitude of the net force on the entire loop is
Physics 202: Lecture 8, Pg 26
Clicker Question 20:
What is the approximate direction of the electric field
at point B?
a)
b)
c)
d)
e)
Left
Right
Up
Down
Zero
Physics 202: Lecture 8, Pg 27
Clicker Question 21:
The light bulbs and batteries in the two circuits are
id i l C
identical.
Compare P1 the
h totall power di
dissipated
i
db
by
circuit 1, with P2 the total power dissipated by circuit
2.
a) P1< P2
b) P1= P2
c) P1> P2
Physics 202: Lecture 8, Pg 28
Clicker Question 22:
The circuit below contains two identical light bulbs
bulbs. If
light bulb B was replaced by a light bulb of twice the
resistance, what would happen to light bulb A?
a) Get dimmer
b) Get brighter
c) Go out
d) Stay the same
e) Not enough information
Physics 202: Lecture 8, Pg 29
Clicker Question 23:
What is the magnitude of the force on q3?
(a)
( )
(b)
(c)
(d)
(e)
F = 1.03 × 10-3 N
F = 2.31 × 10-33 N
F = 4.56 × 10-3 N
F = 11.3
11 3 × 10-33 N
F = 18.6 × 10-3 N
Physics 202: Lecture 8, Pg 30
Clicker Question 24:

A small charged sphere with a mass of 200 g is suspended from
the ceiling by a string as below. A constant electric field of 5 N/C
causes the string to make an angle of 35 with the vertical in
equilibrium. What is the charge on the sphere?
(a)
(b)
(c)
(d)
( )
(e)
3.47 × 10-1 C
5
5.61
61 × 10-11 C
2.74 × 10-1 C
8.34 × 10-1 C
1
1.12
12 × 10-11 C
Physics 202: Lecture 8, Pg 31