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PHYS 102 General Physics-II, Midterm-II

Duration: 100 minutes 21 April 2012

NAME:.................................................................... Section:......................

Q.1 (25) Q.2 (25) Q.3 (25) Q.4 (25) Total (100)

You must sign the Honor Code for your exam to be graded:

I pledge, on my Honor, not to lie, cheat, or steal in either my academicor personal life. I understand that such acts violate the Honor Code and

undermine the community of trust of which we are all stewards.

I agree to abide by this Honor Code during this exam.Signature:

Present your work in a legible and organized format, otherwise you may

lose significant portion of your credit even if your solution is correct!

Solutions will be posted to http://www.fen.bilkent.edu.tr/~phys102/

Dont forget

to sign!

Physics Wiki(No relevance to the exam)

International Thermonuclear Experimental

Reactor (ITER) is an international nuclear fusion

research and engineering project, which is under

construction in France, to be completed in 2019.

ITER is based on the 'tokamak' concept of

magnetic confinement, in which the plasma iscontained in a doughnut-shaped vacuum vessel.

The fuela mixture of deuterium and tritium, two

isotopes of hydrogenis heated to temperatures in

excess of 150 millionC, forming a hot plasma.

Strong magnetic fields are used to keep the plasma

away from the walls. It aims to produce 500 MW

of output power for 50 MW of input power, but

more importantly, to develop technologies and

processes needed for a fusion power plant. Tokamak Source: www.iter.org

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Some expressions from the Textbook which may or may NOT be useful for this exam

(However, you are supposed to know what each symbol means)

Current and current density:

,d

dQI n q A

dt= =

dJ nq=

Resistivity and Ohms Law:

,E

V IRJ

= =

Kirchhoffs Rules:

0 0(junction rule), (loop rule)I V= = Power:

abP V I=

Equivalent Resistance:

1 2(in series)

eq nR R R R= + + +

1 2

1 1 1 1(in parallel)

eq nR R R R

= + + +

Simple R-C Circuit:

Charging:

( ) ( )/( ) /( )

/( ) /( )

0

( ) 1 1

( )

t RC t RC

f

t RC t RC

q t C e Q e

dqi t e I e

dt R

= =

= = =

Discharging:/( )

0

/( )0

( )

( )

t RC

t RC

q t Q e

Qdqi t e

dt RC

=

= =

Magnetic Forces:

mF q B=

(on a point charge q)

mdF I dl B=

(on a current-carrying segment dl

)

Magnetic Flux:

, 0 (for a closed surface)B B dA B dA = =

Magnetic Torque and Potential Energy:

, ,B IA U B = = =

Hall Effect:

x y

z

J Bnq

E

=

Cyclotron Radius:

mR

q B

=

Magnetic Field of a moving charge q:

0

2

4

q rB

r

=

Magnetic Field of a Current-Carrying Segment:

0

2

4

Idl rdB

r

=

Magnetic Field of a Long Straight Wire:

0

2

IB

r

=

Magnetic Force Between Two Parallel Wires:

0

2

IIF

L r

=

Axial Magnetic Field of a Current Loop of Radius a:

0

2x

NIB

a

= (at the center of Ncircular loops)

Amperes Law:

0 enclB dl I =

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