2. Mass is inertia for linear motion. What is rotational inertia? A) mass B) torque C) I / M D) Moment of inertia []
3. Two sinusoidal waves travel in the same direction and have the same frequency. Their amplitudes are y1m and y2m. The smallest possible amplitude of the resultant wave is: A) y1m + y2m and occurs when they are 180° out of phase B) ⎜y1m – y2m⎜ and occurs when they are 180° out of phase C) y1m + y2m and occurs when they are in phase D) ⎜y1m – y2m⎜ and occurs when they are in phase []
8. A standing wave pattern is established in a string as shown. The wavelength of one of the component traveling waves is: _______ _________.
9.. In theYoung’s double-slit system, if one of slits is covered up by a media layer （媒质膜） (n=1.40) and the other is covered up by a media layer (n=1.70), (they have same thickness). After the two media layers are inserted, the original central bright fringe will be replaced by the 7-order bright fringes (屏幕上原中央极大所在点变为第七级明纹), if the wavelength of incident light is 450nm, The thickness of both two layers is__________________________。
= (m + 1/ 2).
D)
n2t = (m + 1 )λ .
2
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II) Fill in the empty space with correct answer:
1. A hoop （环） has a mass of 200 grams and a radius of 25 cm. It rolls without slipping along flat
ground at 500 cm/s. Its total kinetic energy is:___________ __________
2. A particle located at the position vector
rr
=
r (3 i
−
2
r j)
m
has a force
r F
=
r (3 i
vr
=
r (4.0 i
−
r 3.0 j)
should be:___
m
s
.
Its position ____.
4. The phase difference between the positions and the acceleration of objects moving in simple harmonic motion is:____________________.
C) one-fourth
D) four times
[]
7. In an experiment to measure the wavelength of light using a double slit, it is found that
the fringes are too close together to easily count them. To spread out (展开) the fringe pattern
+
r j)
N
acting
on
it.
The torque about the origin should be:___________ ___________
v3ec. tTohr eisverrlo=c(i2ty.0orif+a12.0.r0j)kmg.b. oItdsyanmgouvlainrgmionmtheentxuymplaabnoeuitstghievoenrigbiyn
5.. Two particles do simple harmonic motion of the same amplitude and frequency along closed parallel lines. They pass each other moving in opposite directions each time their displacement is half their amplitude. Then their phase difference is _____ ________.
A) Nπ where N is an integer
B) (N + 1/2)π where N is an integer
C) the angle to the first minimum
D) the angle to the second maximum
[]
9．The resolving power (分辨能力) of a telescope (望远镜) can be increased by:
(I)
(II)
(III)
Total Score
(I) Choose one correct answer among following choices:
1. Three identical objects, each of mass M, are fastened to a massless rod of length L as shown. The rotational inertia about one end of the rod of this array is: A) ML2/2 B) 3ML2/2 C) 5ML2/4 D) 3ML2 []
6. Mass m oscillating on the end of a spring with spring constant k has amplitude A. Its maximum speed is:_______ _______________
7. The displacement of a string is given by y(x,t) = ymsin(kx + ωt). The speed of the wave is: ________________.
to have a
A) greater amplitude.
B) smaller amplitude.
C) lower frequency.
E) higher frequency.
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]
12. A thin film of thickness t and index of refraction n is surrounded by air on both sides.
(条纹花样), one could:
A) halve (减半) the slit separation B) double the slit separation
C) double the width of each slit D) halve the width of each slit
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8．In the equation sinθ = λ/a for single-slit diffraction, θ is:
A) increasing the objective focal length and decreasing the eyepiece focal length
B) increasing the lens diameters
C) decreasing the lens diameters
D) inserting (插入) a correction lens between objective and eyepiece
[]
10. X rays are:
A) rapidly moving protons
B) negatively charged ions (离子)
C) rapidly moving electrons
D) electromagnetic waves
[]
11. The Doppler effect causes the sound from a source moving toward an observer to appear
10. In a stack (排列在一起的) of three polarizing sheets （偏振片） the first and third are crossed (相垂直) while the middle one has its axis at 45° to the axes of the other two. If the intensity of incident unpolarized light is I0, then the intensity of transmitted light by the stack is ( I3 = ):___ ____.