If
two colors of light (not pigments) are combined, one or other of two effects is
noticed. If certain colors are mixed additively, such as red and yellow, the
resulting hue is orange, which is the hue between them in the spectrum. If
certain other colors such as red and blue-green are added, the result is white
light.

Any
two colors which, if added together, give white light are called complementary
colors. Since all the colors added together give white light, they’re
combination may be written symbolically as follows:

**R + O + Y + G + B + V = W**(white)

Also:

**R + BG = W**and**B + V = W**
91.
From the preceding information it can be concluded that: O + Y + G + B + V
gives:

A)
orange….B)
red……C) white…….D) yellow…….E) blue-green

92.The
combination of R + O + G + B + V gives:

A)
blue……B) orange……C) red………D) white…….E) green

93.
The shortest wavelength produced in an X-ray tube operated at 2 million volts
would be: (1 Å = 10

^{-10}m)
A)
1 Å …..B) 0.15 Å…….C) 0.01 Å ……D) 10

^{-5}Å… E) 10^{-4}Å
94.
The de Broglie wavelength associated with neutrons in thermal equilibrium with
matter at 300 K is approximately:

A) 179 Å…….B)

E) 1. 79 Å

**1790 Å…….. C) 17. 9 Å…..D) 0. 179 Å…..**E) 1. 79 Å

95.Two
balls of equal mass are suspended as shown in the diagram below.

The
coefficient of restitution between the balls is equal to 0.5 Ball A after its release strikes ball B with
a force just sufficient to send mass B to a position where the cord supporting
it becomes horizontal. The angle q made by the cord supporting A in its
initial position is given by:

A)
cos
q = 0.5…..B) cos q = 0.25…..C) cos q = 1…..

D) sin q = 2/3….E) cos q = 1 - Ö3

D) sin q = 2/3….E) cos q = 1 - Ö3

96.
At the instant of the collision of the two balls:

A)
the
total kinetic energy is conserved

B)
The
potential energy is decreased

C)
The
Hamiltonian is conserved

D)
The
kinetic energy is increased

E)
Part
of the kinetic energy is changed to heat

97.If
the coefficient of restitution was equal to 1, then we would have a

*completely elastic collision*and assuming ball B is at rest when A collides with it:
A)
Ball
A will be at rest after the collision

B)
Ball
A will move with ball B in the same direction if sin q

__>__0.5
C)
Ball
A will move in the opposite direction to ball B.

D)
Both
balls will be at rest after the collision.

E)
Ball
B will be in s standing position.

98.
The electric (E-) field in an electromagnetic wave is described the relation:

E(

__r____,__t) = (e_{1}E_{1}+ e_{2 }E_{2}) exp [ (ik**- iwt)**__r__
Where e

_{1}and e_{2 }are two mutually orthogonal unit vectors, both of which are perpendicular to k, and E_{1}and E_{2}are two real numbers. (For right circular polarization of an electric wave, the electric vector rotates in the clockwise direction when an observer faces into the oncoming wave).
This
electromagnetic wave is:

A)
plane
polarized……B) right circularly polarized

C)
left circularly polarized……D) elliptically polarized E) unpolarized

99.
If: E

_{2}= i E_{1}then the electromagnetic wave is:
B)
A)
plane polarized…..B) right circularly polarized

C)
left circularly polarized……D) elliptically polarized E) unpolarized

100.
A ray of light strikes at normal incidence a thin transparent film (index of
refraction = n). Reinforcement of the reflected ray will occur when the film
thickness, in terms of the wavelength of the incident light, equals:

A)
¼ …..B) ¼
n ……C) ½ ….D) 1/ (2n)
….E) 9/ (8n)

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