Question 1

The rate of energy transport of an electromagnetic wave per unit area is given by:

Accepted Answer

A) the vector 
B) the Poynting vector 
C) the Poynting vector divided by the area 
D) the Poynting vector divided by time 
E) the Poynting vector multiplied by time 
A) the vector 
B) the Poynting vector 
C) the Poynting vector divided by the area 
D) the Poynting vector divided by time 
E) the Poynting vector multiplied by time

Question 2

Light with an intensity of 1 kW/m2 falls normally on a surface with an area of 1 cm2 and is completely reflected.The force of the radiation on the surface is:

Accepted Answer

A) 3.3 * 10-11 N 
B) 1.7 * 10-10 N 
C) 3.3 * 10-10 N 
D) 6.7 * 10-10 N 
E) 1.0 *10-4 N 
A) 3.3 * 10-11 N 
B) 1.7 * 10-10 N 
C) 3.3 * 10-10 N 
D) 6.7 * 10-10 N 
E) 1.0 *10-4 N

Question 3

The critical angle for total internal reflection at a diamond-air interface is 25$\degree$.Suppose light is incident at an angle of $\theta$with the normal.Total internal reflection will occur if the incident medium is:

Accepted Answer

A) air and $\theta$= 25$\degree$ 
B) air and $\theta$> 25$\degree$ 
C) air and $\theta$ 25$\degree$ 
A) air and $\theta$= 25$\degree$ 
B) air and $\theta$> 25$\degree$ 
C) air and $\theta$ 25$\degree$

Question 4

Light from any ordinary source (such as a flame)is usually:

Accepted Answer

A) unpolarized 
B) plane polarized 
C) circularly polarized 
D) elliptically polarized 
E) monochromatic 
A) unpolarized 
B) plane polarized 
C) circularly polarized 
D) elliptically polarized 
E) monochromatic

Question 5

A transmitter consists of an LC circuit with an inductance of 15 µH and a capacitance of 23 pF.What is the wavelength of the electromagnetic waves it emits?

Accepted Answer

A) 29 mm 
B) 65 mm 
C) 5.6 m 
D) 35 m 
E) 220 m 
A) 29 mm 
B) 65 mm 
C) 5.6 m 
D) 35 m 
E) 220 m

Question 6

When light passes from air to glass, it bends:

Accepted Answer

A) toward the normal without changing speed 
B) toward the normal and slows down 
C) toward the normal and speeds up 
D) away from the normal and slows down 
E) away from the normal and speeds up 
A) toward the normal without changing speed 
B) toward the normal and slows down 
C) toward the normal and speeds up 
D) away from the normal and slows down 
E) away from the normal and speeds up

Question 7

The relation n1sin $\theta$1 = n2 sin $\theta$2 which applies as a ray of light strikes an interface between two media, is known as:

Accepted Answer

A) Gauss' law 
B) Snell's law 
C) Faraday's law 
D) Cole's law 
E) law of sines 
A) Gauss' law 
B) Snell's law 
C) Faraday's law 
D) Cole's law 
E) law of sines

Question 8

The index of refraction of a substance is:

Accepted Answer

A) the speed of light in the substance 
B) the angle of refraction 
C) the angle of incidence 
D) the speed of light in vacuum divided by the speed of light in the substance 
E) measured in radians 
A) the speed of light in the substance 
B) the angle of refraction 
C) the angle of incidence 
D) the speed of light in vacuum divided by the speed of light in the substance 
E) measured in radians

Question 9

If the magnetic field in a plane electromagnetic wave is along the y axis and its magnitude is given by Bm sin (kx - $ \omega $t)in SI units, then the electric field is along the z axis and its magnitude is given by

Accepted Answer

A) (cBm)cos (kx - $ \omega $t) 
B) -(cBm)cos (kx - $ \omega $t) 
C) (cBm)sin (kx - $ \omega $t) 
D) -(cBm)sin (kx - $ \omega $t) 
E) Bm cos (kx - $ \omega $t) 
A) (cBm)cos (kx - $ \omega $t) 
B) -(cBm)cos (kx - $ \omega $t) 
C) (cBm)sin (kx - $ \omega $t) 
D) -(cBm)sin (kx - $ \omega $t) 
E) Bm cos (kx - $ \omega $t)

Question 10

Light with an intensity of 1 kW/m2 falls normally on a surface with an area of 1 cm2 and is completely absorbed.The force of the radiation on the surface is:

Accepted Answer

A) 3.3 *10-11 N 
B) 1.7 *10-10 N 
C) 3.3 *10-10 N 
D) 6.7 * 10-10 N 
E) 1.0 *10-4 N 
A) 3.3 *10-11 N 
B) 1.7 *10-10 N 
C) 3.3 *10-10 N 
D) 6.7 * 10-10 N 
E) 1.0 *10-4 N

Question 11

Light of uniform intensity shines perpendicularly on a totally absorbing surface, fully illuminating the surface.If the area of the surface is decreased:

Accepted Answer

A) the radiation pressure increases and the radiation force increases 
B) the radiation pressure increases and the radiation force decreases 
C) the radiation pressure stays the same and the radiation force increases 
D) the radiation pressure stays the same and the radiation force decreases 
E) the radiation pressure decreases and the radiation force decreases 
A) the radiation pressure increases and the radiation force increases 
B) the radiation pressure increases and the radiation force decreases 
C) the radiation pressure stays the same and the radiation force increases 
D) the radiation pressure stays the same and the radiation force decreases 
E) the radiation pressure decreases and the radiation force decreases

Question 12

In a stack of three polarizing sheets the first and third are crossed while the middle one has its axis at 45$\degree$ to the axes of the other two.The fraction of the intensity of an incident unpolarized beam of light that is transmitted by the stack is:

Accepted Answer

A) 1/2 
B) 1/3 
C) 1/4 
D) 1/8 
E) 0 
A) 1/2 
B) 1/3 
C) 1/4 
D) 1/8 
E) 0

Question 13

Light with an intensity of 1 kW/m2 falls normally on a surface and is completely reflected.The radiation pressure is:

Accepted Answer

A) 1 kPa 
B) 3 *1011 Pa 
C) 1.7 * 10-6 Pa 
D) 3.3 * 10-6 Pa 
E) 6.7*10-6 Pa 
A) 1 kPa 
B) 3 *1011 Pa 
C) 1.7 * 10-6 Pa 
D) 3.3 * 10-6 Pa 
E) 6.7*10-6 Pa

Question 14

As light goes from one medium to another, it is bent away from the normal.Then:

Accepted Answer

A) the speed of the light has increased 
B) dispersion must occur 
C) the second medium has a higher index of refraction 
D) no change in speed has occurred 
E) refraction has not occurred because refraction means a bending toward the normal 
A) the speed of the light has increased 
B) dispersion must occur 
C) the second medium has a higher index of refraction 
D) no change in speed has occurred 
E) refraction has not occurred because refraction means a bending toward the normal

Question 15

Of the following human eyes are most sensitive to:

Accepted Answer

A) red light 
B) violet light 
C) blue light 
D) green light 
E) none of these (they are equally sensitive to all colors) 
A) red light 
B) violet light 
C) blue light 
D) green light 
E) none of these (they are equally sensitive to all colors)

Question 16

The light intensity 10 m from a point source is 1000 W/m2.The intensity 100 m from the same source is:

Accepted Answer

A) 1000 W/m2 
B) 100 W/m2 
C) 10 W/m2 
D) 1 W/m2 
E) 0.1 W/m2 
A) 1000 W/m2 
B) 100 W/m2 
C) 10 W/m2 
D) 1 W/m2 
E) 0.1 W/m2

Question 17

The time for a radar signal to travel to the Moon and back, a one-way distance of about 3.8 *108 m, is:

Accepted Answer

A) 1.3 s 
B) 2.5 s 
C) 8 s 
D) 8 min 
E) 1 * 106 s 
A) 1.3 s 
B) 2.5 s 
C) 8 s 
D) 8 min 
E) 1 * 106 s

Question 18

If nwater = 1.33, what is the angle of refraction for the ray shown?

Accepted Answer

A) 19$\degree$ 
B) 22$\degree$ 
C) 40$\degree$ 
D) 42$\degree$ 
E) 48$\degree$ 
A) 19$\degree$ 
B) 22$\degree$ 
C) 40$\degree$ 
D) 42$\degree$ 
E) 48$\degree$

Question 19

When light travels from medium X to medium Y as shown:

Accepted Answer

A) both the speed and the frequency decrease 
B) both the speed and the frequency increase 
C) both the speed and the wavelength decrease 
D) both the speed and the wavelength increase 
E) both the wavelength and the frequency are unchanged 
A) both the speed and the frequency decrease 
B) both the speed and the frequency increase 
C) both the speed and the wavelength decrease 
D) both the speed and the wavelength increase 
E) both the wavelength and the frequency are unchanged

Question 20

Which diagram below illustrates the path of a light ray as it travels from a given point X in air to another given point Y in glass?

Accepted Answer

A) I 
B) II 
C) III 
D) IV 
E) V 
A) I 
B) II 
C) III 
D) IV 
E) V

Exam 33: Electromagnetic Waves

The rate of energy transport of an electromagnetic wave per unit area is given by:

Light with an intensity of 1 kW/m2 falls normally on a surface with an area of 1 cm2 and is completely reflected.The force of the radiation on the surface is:

The critical angle for total internal reflection at a diamond-air interface is 25 °\degree° .Suppose light is incident at an angle of θ\thetaθ with the normal.Total internal reflection will occur if the incident medium is:

Light from any ordinary source (such as a flame)is usually:

A transmitter consists of an LC circuit with an inductance of 15 µH and a capacitance of 23 pF.What is the wavelength of the electromagnetic waves it emits?

When light passes from air to glass, it bends:

The relation n1sin θ\thetaθ 1 = n2 sin θ\thetaθ 2 which applies as a ray of light strikes an interface between two media, is known as:

The index of refraction of a substance is:

If the magnetic field in a plane electromagnetic wave is along the y axis and its magnitude is given by Bm sin (kx - ω \omega ω t)in SI units, then the electric field is along the z axis and its magnitude is given by

Light with an intensity of 1 kW/m2 falls normally on a surface with an area of 1 cm2 and is completely absorbed.The force of the radiation on the surface is:

Light of uniform intensity shines perpendicularly on a totally absorbing surface, fully illuminating the surface.If the area of the surface is decreased:

In a stack of three polarizing sheets the first and third are crossed while the middle one has its axis at 45 °\degree° to the axes of the other two.The fraction of the intensity of an incident unpolarized beam of light that is transmitted by the stack is:

Light with an intensity of 1 kW/m2 falls normally on a surface and is completely reflected.The radiation pressure is:

As light goes from one medium to another, it is bent away from the normal.Then:

Of the following human eyes are most sensitive to:

The light intensity 10 m from a point source is 1000 W/m2.The intensity 100 m from the same source is:

The time for a radar signal to travel to the Moon and back, a one-way distance of about 3.8 *108 m, is:

If nwater = 1.33, what is the angle of refraction for the ray shown?

When light travels from medium X to medium Y as shown:

Which diagram below illustrates the path of a light ray as it travels from a given point X in air to another given point Y in glass?

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Light with an intensity of 1 kW/m² falls normally on a surface with an area of 1 cm² and is completely reflected.The force of the radiation on the surface is:

The critical angle for total internal reflection at a diamond-air interface is 25 $\degree$ .Suppose light is incident at an angle of $\theta$ with the normal.Total internal reflection will occur if the incident medium is:

The relation n₁sin $\theta$ ₁ = n₂ sin $\theta$ ₂ which applies as a ray of light strikes an interface between two media, is known as:

If the magnetic field in a plane electromagnetic wave is along the y axis and its magnitude is given by B_m sin (kx - $\omega$ t)in SI units, then the electric field is along the z axis and its magnitude is given by

Light with an intensity of 1 kW/m² falls normally on a surface with an area of 1 cm² and is completely absorbed.The force of the radiation on the surface is:

In a stack of three polarizing sheets the first and third are crossed while the middle one has its axis at 45 $\degree$ to the axes of the other two.The fraction of the intensity of an incident unpolarized beam of light that is transmitted by the stack is:

Light with an intensity of 1 kW/m² falls normally on a surface and is completely reflected.The radiation pressure is:

The light intensity 10 m from a point source is 1000 W/m².The intensity 100 m from the same source is:

The time for a radar signal to travel to the Moon and back, a one-way distance of about 3.8 *10⁸ m, is:

If n_water = 1.33, what is the angle of refraction for the ray shown? $If n<sub>water</sub> = 1.33, what is the angle of refraction for the ray shown?$