Question 1

Light is an electromagnetic wave.When visible light is plane polarized,

Accepted Answer

A) the electric-field vector is parallel to the magnetic-field vector. 
B) the electric-field vector is parallel to the direction of propagation. 
C) the electric-field vector is in a fixed direction perpendicular to the direction of propagation,but the magnetic-field vector may be in any direction. 
D) the electric-field vector is in a fixed direction perpendicular to the direction of propagation,and the magnetic-field vector is perpendicular to the electric-field vector. 
E) None of these is correct. 
A) the electric-field vector is parallel to the magnetic-field vector. 
B) the electric-field vector is parallel to the direction of propagation. 
C) the electric-field vector is in a fixed direction perpendicular to the direction of propagation,but the magnetic-field vector may be in any direction. 
D) the electric-field vector is in a fixed direction perpendicular to the direction of propagation,and the magnetic-field vector is perpendicular to the electric-field vector. 
E) None of these is correct. D

Question 2

The critical angle for light rays passing from flint glass (n = 1.70)into air is about

Accepted Answer

A) 3.4º 
B) 36º 
C) 44º 
D) 54º 
E) 90º 
A) 3.4º 
B) 36º 
C) 44º 
D) 54º 
E) 90º B

Question 3

A helium-neon laser emits light of wavelength 632.8 nm and has a power output of 1.5 mW.How many photons are emitted per second by this laser?

Accepted Answer

A) 1.34 $\times$ 1014  
B) 2.56 $\times$ 1015  
C) 3.09 $\times$ 1015  
D) 4.22 $\times$ 1015  
E) 4.78 $\times$ 1015  
A) 1.34 $\times$ 1014  
B) 2.56 $\times$ 1015  
C) 3.09 $\times$ 1015  
D) 4.22 $\times$ 1015  
E) 4.78 $\times$ 1015  E

Question 4

It has been suggested that a fundamental physical unit of time is the time required for light to traverse the diameter of the nucleus of an atom (approximately 3 $\times$ 10-13 m).This unit of time is approximately

Accepted Answer

A) 1 s 
B) 10-4 s 
C) 2 $\times$ 10-20 s 
D) 10-21 s 
E) 10-23 s 
A) 1 s 
B) 10-4 s 
C) 2 $\times$ 10-20 s 
D) 10-21 s 
E) 10-23 s

Question 5

If you look at a dot on a piece of paper through a calcite crystal lying on the paper,you will see two images of the dot,one of which appears to be nearer to you than the other.From this evidence you can conclude that

Accepted Answer

A) the beams from both images are polarized. 
B) calcite has different indices of refraction for the two beams. 
C) there is interference between the two beams. 
D) the calcite has increased the resolving power of your eye. 
E) the appearance is due to diffraction. 
A) the beams from both images are polarized. 
B) calcite has different indices of refraction for the two beams. 
C) there is interference between the two beams. 
D) the calcite has increased the resolving power of your eye. 
E) the appearance is due to diffraction.

Question 6

Use the following figure below for the next problem.   
The figure shows a cross-
-A fiber optic is made by cladding a thin fiber core of refractive index n1 = 1.45 with a material of refractive index n2 = 1.38.What is the maximum incident angle,$\theta$,so that the light ray is totally internally reflected inside the fiber?

Accepted Answer

A) 24.1º 
B) 26.4º 
C) 28.2º 
D) 30.3º 
E) 32.7º 
A) 24.1º 
B) 26.4º 
C) 28.2º 
D) 30.3º 
E) 32.7º

Question 7

Of the following quantities,the one that is independent of the frequency of light is the

Accepted Answer

A) polarizing angle. 
B) critical angle. 
C) angle of minimum deviation. 
D) angle of refraction. 
E) angle of reflection. 
A) polarizing angle. 
B) critical angle. 
C) angle of minimum deviation. 
D) angle of refraction. 
E) angle of reflection.

Question 8

Light known to be polarized in the horizontal direction is incident on a polarizing sheet.It is observed that only 15 percent of the intensity of the incident light is transmitted through the sheet.What angle does the transmission axis of the sheet make with the horizontal?

Accepted Answer

A) 8.6º 
B) 21º 
C) 23º 
D) 67º 
E) 81º 
A) 8.6º 
B) 21º 
C) 23º 
D) 67º 
E) 81º

Question 9

Light is incident on a piece of glass in air at an angle of 37.0º from the normal.If the index of refraction of the glass is 1.50,the angle that the refracted ray makes with the normal is approximately

Accepted Answer

A) 8.6º 
B) 21.8º 
C) 23.6º 
D) 41.8º 
E) 56.4º 
A) 8.6º 
B) 21.8º 
C) 23.6º 
D) 41.8º 
E) 56.4º

Question 10

Use the following figure below for the next problem.   
The figure shows a cross-
-A fiber optic is made by cladding a thin fiber core of refractive index n1 = 1.45 with a material of refractive index n2 = 1.38.The numerical aperture of a fiber optic is defined as NA = nair sin $\theta$m,where $\theta$m is the maximum incident angle so that the light ray is totally internally reflected inside the fiber.The NA for the fiber is

Accepted Answer

A) 0.445 
B) 0.614 
C) 0.645 
D) 0.407 
E) 0.470 
A) 0.445 
B) 0.614 
C) 0.645 
D) 0.407 
E) 0.470

Question 11

The energy of an electromagnetic wave that is in the red region of the visible spectrum is approximately

Accepted Answer

A) 1 eV 
B) 2 eV 
C) 3 eV 
D) 4 eV 
E) 5 eV 
A) 1 eV 
B) 2 eV 
C) 3 eV 
D) 4 eV 
E) 5 eV

Question 12

An unpolarized beam of light is incident on a group of three polarizing sheets that are lined up so that the characteristic direction of each is rotated by 45º clockwise with respect to the preceding sheet.The fraction of the incident intensity Io that is transmitted is

Accepted Answer

A) zero 
B) Io/2 
C) Io/4 
D) Io/6 
E) Io/8 
A) zero 
B) Io/2 
C) Io/4 
D) Io/6 
E) Io/8

Question 13

One would not attempt to polarize light by

Accepted Answer

A) selective absorption. 
B) reflection from a surface. 
C) passage through a narrow slit. 
D) scattering. 
E) double refraction. 
A) selective absorption. 
B) reflection from a surface. 
C) passage through a narrow slit. 
D) scattering. 
E) double refraction.

Question 14

A 60S1U1P1$\circ$S1S1P0 prism has a refractive index of 1.64 for blue light and 1.61 for red light.Calculate the difference in the angle of emergence from the opposite face of the prism for a beam of red and a beam of blue light that are both incident at an angle of 60o.

Accepted Answer

A) 0.4S1U1P1$\circ$S1S1P0 
B) 0.0S1U1P1$\circ$S1S1P0 
C) 1.3S1U1P1$\circ$S1S1P0 
D) 3.9S1U1P1$\circ$S1S1P0 
E) 2.7S1U1P1$\circ$S1S1P0 
A) 0.4S1U1P1$\circ$S1S1P0 
B) 0.0S1U1P1$\circ$S1S1P0 
C) 1.3S1U1P1$\circ$S1S1P0 
D) 3.9S1U1P1$\circ$S1S1P0 
E) 2.7S1U1P1$\circ$S1S1P0

Question 15

If the refractive index of glass is 1.5 and the refractive index of a particular liquid is 1.38,then calculate the value for the critical angle of total internal reflection at the liquid-glass interface.

Accepted Answer

A) 23.1S1U1P1$\circ$S1S1P0 
B) 66.9S1U1P1$\circ$S1S1P0 
C) 82.8S1U1P1$\circ$S1S1P0 
D) 42.6S1U1P1$\circ$S1S1P0 
E) None of these is correct. 
A) 23.1S1U1P1$\circ$S1S1P0 
B) 66.9S1U1P1$\circ$S1S1P0 
C) 82.8S1U1P1$\circ$S1S1P0 
D) 42.6S1U1P1$\circ$S1S1P0 
E) None of these is correct.

Question 16

From directly above,you're watching a fish swim 1.83 m beneath the surface of a clear lake (n = 1.33).How far beneath the surface does the fish seem to be?

Accepted Answer

A) 0.914 m 
B) 1.37 m 
C) 1.83 m 
D) 2.44 m 
E) 2.93 m 
A) 0.914 m 
B) 1.37 m 
C) 1.83 m 
D) 2.44 m 
E) 2.93 m

Question 17

The lifetime of a typical excited atomic energy state is of the order of

Accepted Answer

A) 10-6 s 
B) 10-7 s 
C) 10-8 s 
D) 10-9 s 
E) 10-10 s 
A) 10-6 s 
B) 10-7 s 
C) 10-8 s 
D) 10-9 s 
E) 10-10 s

Question 18

The dependence of the index of refraction on wavelength is called dispersion.A beam of light (in air)containing red and blue light is incident at an angle of 35S1U1P1$\circ$S1S1P0 on a glass plate that has an index of refraction of 1.64 for blue light and 1.61 for red light.By what percent does the speed of the red light exceed that of the blue light inside the glass,i.e.calculate (v(red)-v(blue))* 100 / v(red)?

Accepted Answer

A) 1.1% 
B) 1.8% 
C) 0.53% 
D) The speed is the same for both colors. 
E) 0.019% 
A) 1.1% 
B) 1.8% 
C) 0.53% 
D) The speed is the same for both colors. 
E) 0.019%

Question 19

A light wave is like a sound wave in that both

Accepted Answer

A) are longitudinal waves. 
B) are means of transmitting energy. 
C) are transverse waves. 
D) require a material medium for propagation. 
E) have the same velocity in air. 
A) are longitudinal waves. 
B) are means of transmitting energy. 
C) are transverse waves. 
D) require a material medium for propagation. 
E) have the same velocity in air.

Question 20

The index of refraction of water is approximately 1.33.The angle of incidence for maximum polarization by reflection from water is approximately

Accepted Answer

A) 57º 
B) 53º 
C) 45º 
D) 37º 
E) 33º 
A) 57º 
B) 53º 
C) 45º 
D) 37º 
E) 33º

Exam 31: Properties of Light

Light is an electromagnetic wave.When visible light is plane polarized,

The critical angle for light rays passing from flint glass (n = 1.70)into air is about

A helium-neon laser emits light of wavelength 632.8 nm and has a power output of 1.5 mW.How many photons are emitted per second by this laser?

It has been suggested that a fundamental physical unit of time is the time required for light to traverse the diameter of the nucleus of an atom (approximately 3 ×\times× 10-13 m).This unit of time is approximately

If you look at a dot on a piece of paper through a calcite crystal lying on the paper,you will see two images of the dot,one of which appears to be nearer to you than the other.From this evidence you can conclude that

Of the following quantities,the one that is independent of the frequency of light is the

Light known to be polarized in the horizontal direction is incident on a polarizing sheet.It is observed that only 15 percent of the intensity of the incident light is transmitted through the sheet.What angle does the transmission axis of the sheet make with the horizontal?

Light is incident on a piece of glass in air at an angle of 37.0º from the normal.If the index of refraction of the glass is 1.50,the angle that the refracted ray makes with the normal is approximately

The energy of an electromagnetic wave that is in the red region of the visible spectrum is approximately

An unpolarized beam of light is incident on a group of three polarizing sheets that are lined up so that the characteristic direction of each is rotated by 45º clockwise with respect to the preceding sheet.The fraction of the incident intensity Io that is transmitted is

One would not attempt to polarize light by

A 60 ∘\circ∘ prism has a refractive index of 1.64 for blue light and 1.61 for red light.Calculate the difference in the angle of emergence from the opposite face of the prism for a beam of red and a beam of blue light that are both incident at an angle of 60o.

If the refractive index of glass is 1.5 and the refractive index of a particular liquid is 1.38,then calculate the value for the critical angle of total internal reflection at the liquid-glass interface.

From directly above,you're watching a fish swim 1.83 m beneath the surface of a clear lake (n = 1.33).How far beneath the surface does the fish seem to be?

The lifetime of a typical excited atomic energy state is of the order of

A light wave is like a sound wave in that both

The index of refraction of water is approximately 1.33.The angle of incidence for maximum polarization by reflection from water is approximately

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It has been suggested that a fundamental physical unit of time is the time required for light to traverse the diameter of the nucleus of an atom (approximately 3 $\times$ 10^-13 m).This unit of time is approximately

An unpolarized beam of light is incident on a group of three polarizing sheets that are lined up so that the characteristic direction of each is rotated by 45º clockwise with respect to the preceding sheet.The fraction of the incident intensity I_o that is transmitted is

A 60^$\circ$ prism has a refractive index of 1.64 for blue light and 1.61 for red light.Calculate the difference in the angle of emergence from the opposite face of the prism for a beam of red and a beam of blue light that are both incident at an angle of 60^o.