Question 1

Which of the following exert the smallest amount of radiation pressure?

Accepted Answer

A) a 1 mW laser pointer on a 2mm diameter spot 1 m away 
B) a 200 W light bulb on a 4mm diameter spot 10m away 
C) a 100 W light bulb on a 2 mm diameter spot 4 m away 
D) a 200 W light bulb on a 2 mm diameter spot 5 m away 
E) All of the choices exert the same pressure. 
A) a 1 mW laser pointer on a 2mm diameter spot 1 m away 
B) a 200 W light bulb on a 4mm diameter spot 10m away 
C) a 100 W light bulb on a 2 mm diameter spot 4 m away 
D) a 200 W light bulb on a 2 mm diameter spot 5 m away 
E) All of the choices exert the same pressure.

Question 2

Sunlight is coming straight down on a solar panel (length 1.25 m and width W=0.850 m)belonging to the Spirit Mars rover.The amplitude of the electric field in the solar radiation is 642 V/m and is uniform (the radiation has the same amplitude everywhere).Find the efficiency of the solar panel if average electrical power converted from the solar radiation is 131 W.

Accepted Answer

A) 20.4 % 
B) 26.0 % 
C) 18.9 % 
D) 22.6% 
E) 24.5 % 
A) 20.4 % 
B) 26.0 % 
C) 18.9 % 
D) 22.6% 
E) 24.5 %

Question 3

A beam of unpolarized light with an intensity of 1000 W/m2 impinges on a set of two linear polarizers with their polarization axes at an angle $\theta$ relative to each other.If the light transmitted through this combination has an intensity of 250 W/m2,what is $\theta$?

Accepted Answer

A) 0S1U1P1$\circ$S1S1P0 
B) 22.5S1U1P1$\circ$S1S1P0 
C) 45S1U1P1$\circ$S1S1P0 
D) 67.5S1U1P1$\circ$S1S1P0 
E) 90S1U1P1$\circ$S1S1P0 
A) 0S1U1P1$\circ$S1S1P0 
B) 22.5S1U1P1$\circ$S1S1P0 
C) 45S1U1P1$\circ$S1S1P0 
D) 67.5S1U1P1$\circ$S1S1P0 
E) 90S1U1P1$\circ$S1S1P0

Question 4

Unpolarized light of intensity 200 W/m2 is incident on a polarizer A. Light leaving this polarizer is then incident on a polarizer B with its polarization axis oriented at 30S1U1P1$\circ$S1S1P0 with respect to that of A. What is the intensity of the light leaving polarizer B?

Accepted Answer

A)   25 W/m2  
B)   75 W/m2 
C)   100 W/m2  
D)   150 W/m2  
E)   200 W/m2  
A)   25 W/m2  
B)   75 W/m2 
C)   100 W/m2  
D)   150 W/m2  
E)   200 W/m2

Question 5

A parallel plate capacitor with radius 21 cm is connected in series with a 15-V battery.A switch is thrown which causes the capacitor to discharge through a 150-$\varOmega$ resistor.What is the displacement current between the plates at this time?

Accepted Answer

A) 0.10 A 
B) 0.20 mA 
C) 0.14 A 
D) You need to know the separation of the plates. 
A) 0.10 A 
B) 0.20 mA 
C) 0.14 A 
D) You need to know the separation of the plates.

Question 6

Unpolarized light with intensity I0 is incident on a polarizer as shown.After passing through the first polarizer,the light has intensity I1.This light passes through a second polarizer that is rotated 45S1U1P1$\circ$S1S1P0 with respect to the first polarizer.The light now with intensity I2 passes through a third polarizer that is rotated 90S1U1P1$\circ$S1S1P0 with respect to the first polarizer.The intensity of light after the third polarizer is I3.Pick the one correct statement from the following statements.

Accepted Answer

A) I3 = 0 
B) I3 = I0/8 
C) I3 = I0/3 
D) I3 = 2I0 
E) I3 = I0/2 
A) I3 = 0 
B) I3 = I0/8 
C) I3 = I0/3 
D) I3 = 2I0 
E) I3 = I0/2

Question 7

Which waves have the longest wavelength in the electromagnetic spectrum?

Accepted Answer

A) gamma rays 
B) ultraviolet light 
C) visible light 
D) radio waves 
A) gamma rays 
B) ultraviolet light 
C) visible light 
D) radio waves

Question 8

What is the distance between successive heating anti-nodes in a microwave oven's cavity? The microwave oven uses 1200 W and uses a frequency of 2.4 Gigahertz.

Accepted Answer

A) 0.30 mm 
B) 0.60 mm 
C) 6.3 cm 
D) 13 cm 
E) 26 cm 
A) 0.30 mm 
B) 0.60 mm 
C) 6.3 cm 
D) 13 cm 
E) 26 cm

Question 9

A house with a south-facing roof installs photovoltaic panels on its roof to generate electricity.The photovoltaic panels have an efficiency of 10% and occupy an area with a size of 5.0 m by 8.0 m.The average solar radiation on the panels is 250 W/m2,when averaged over day/night,summer/winter,cloudy/sunny,etc.How many kilowatt-hours of electrical energy will the solar panels generate in a 30-day month?

Accepted Answer

A) 720 kW-hr 
B) 1000 kW-hr 
C) 1200 kW-hr 
D) 1500 kW-hr 
E) 10000 kW-hr 
A) 720 kW-hr 
B) 1000 kW-hr 
C) 1200 kW-hr 
D) 1500 kW-hr 
E) 10000 kW-hr

Question 10

A laser produces linearly polarized light that is polarized in the vertical direction.The light travels in the +y-direction and passes through two polarizers.The polarization axis of the first polarizer is tipped towards the negative x-axis at 24S1U1P1$\circ$S1S1P0 from vertical (z-axis).The polarization axis of the second polarizer is tipped towards the positive x-axis at 15S1U1P1$\circ$S1S1P0 from vertical (z-axis).The laser beam is collimated (neither converging nor expanding),has a circular cross section with a diameter of 1.00 mm,and has an average power of 15 mW.What is the average power of the laser beam after passing through both polarizers?

Accepted Answer

A) 3.75 W 
B) 7.56 W 
C) 10.6 W 
D) 11.7 W 
E) 12.5 W 
A) 3.75 W 
B) 7.56 W 
C) 10.6 W 
D) 11.7 W 
E) 12.5 W

Question 11

A focused 100 W spotlight delivers 50% of its light into a circle with a diameter of 50 cm.What is the average rms electric field in this illuminated area?

Accepted Answer

A) 150 V/m 
B) 190 V/m 
C) 250 V/m 
D) 310 V/m 
E) 440 V/m 
A) 150 V/m 
B) 190 V/m 
C) 250 V/m 
D) 310 V/m 
E) 440 V/m

Question 12

A green laser beam with a wavelength of 515 nm is transmitting a signal to a satellite.If it takes 1.0 ms for the signal to reach the satellite,how far away is the satellite?

Accepted Answer

A) 300 km 
B) 515 km 
C) 1900 km 
D) 3300 km 
E) 300,000 km 
A) 300 km 
B) 515 km 
C) 1900 km 
D) 3300 km 
E) 300,000 km

Question 13

A parallel plate capacitor with circular plates of radius 10.0 cm are separated by a distance of 5.0 mm.The potential across the capacitor is increased at a constant rate of 120 V/s.Find the distance from the center of the plates and between the plates (r-15 T.

Accepted Answer

A) 5.0 cm 
B) 1.4 cm 
C) 2.7 cm 
D) 7.1 cm 
A) 5.0 cm 
B) 1.4 cm 
C) 2.7 cm 
D) 7.1 cm

Question 14

Unpolarized light of intensity 100 mW/m2 passes through two filters.The first filter has an alignment of 30.0 degrees from the vertical and the second has an alignment of 80.0 degrees from the vertical.What is the intensity of the light that passes through the second filter?

Accepted Answer

A) 1.1 mW/m2 
B) 2.3 mW/m2 
C) 21 mW/m2 
D) 24 mW/m2 
E) 41 mW/m2 
A) 1.1 mW/m2 
B) 2.3 mW/m2 
C) 21 mW/m2 
D) 24 mW/m2 
E) 41 mW/m2

Question 15

An electric field of 100 V/m is directed outward from the plane of a circular area with radius 4.0 cm.If the electric field increases at a rate of 10 V/ms,determine the magnitude of the magnetic field at a radial distance 10.0 cm away from the center of the circular area.

Accepted Answer

A) 1.1 * 10-15 T 
B) 3.4 * 10-15 T 
C) 5.9 * 10-15 T 
D) 8.9 * 10-15 T 
E) 9.7 * 10-15 T 
A) 1.1 * 10-15 T 
B) 3.4 * 10-15 T 
C) 5.9 * 10-15 T 
D) 8.9 * 10-15 T 
E) 9.7 * 10-15 T

Question 16

The potential across a 10.0-mF capacitor is increasing at a rate of 120 V/s.What is the displacement current through the capacitor?

Accepted Answer

A) 1.20 A 
B) 10.0 A 
C) 120 A 
D) None are correct. 
A) 1.20 A 
B) 10.0 A 
C) 120 A 
D) None are correct.

Question 17

A plane parallel plate capacitor has air between plates and disc shaped plates of radius 3.0 mm that are coaxial and 2.5 mm apart.Charge is being accumulated on the plates of the capacitor.What is the displacement current between the plates at an instant when the time rate of charge accumulation on the plates is 1.5 $\mu$C/s?

Accepted Answer

A) 1.0 * 10-6 A 
B) 1.5 * 10-6 A 
C) 2.0 * 10-6 A 
D) 2.5 * 10-6 A 
E) 3.0 * 10-6 A 
A) 1.0 * 10-6 A 
B) 1.5 * 10-6 A 
C) 2.0 * 10-6 A 
D) 2.5 * 10-6 A 
E) 3.0 * 10-6 A

Question 18

In outer space,there are two astronauts at rest,one 20.0 m from the space shuttle and the other 40.0 m away from the shuttle.By using a 20-W laser,the astronaut located 40.0 m away from the shuttle decides to propel the other astronaut towards the space shuttle.He focuses the laser on a piece of totally reflecting fabric on her space suit.If her total mass with equipment is 100 kg,how long will it take her to reach the space shuttle?

Accepted Answer

A) 2.2 hours 
B) 10 hours 
C) 23 hours 
D) 48 hours 
A) 2.2 hours 
B) 10 hours 
C) 23 hours 
D) 48 hours

Question 19

The amplitude of the electric field of an electromagnetic wave is 21 V/m.The amplitude of the magnetic field of the wave is

Accepted Answer

A) 63 * 10-8 T. 
B) 49 * 10-8 T. 
C) 31* 10-8 T. 
D) 7 * 10-8 T. 
A) 63 * 10-8 T. 
B) 49 * 10-8 T. 
C) 31* 10-8 T. 
D) 7 * 10-8 T.

Question 20

The amplitude of the electric field detected by an FM radio receiver is 400 µV/m.The intensity of the signal is

Accepted Answer

A) 1.2 * 10-10 W/m2. 
B) 2.1 * 10-10 W/m2. 
C) 2.4 * 10-10 W/m2. 
D) 9.8 * 10-10 W/m2. 
A) 1.2 * 10-10 W/m2. 
B) 2.1 * 10-10 W/m2. 
C) 2.4 * 10-10 W/m2. 
D) 9.8 * 10-10 W/m2.

Exam 31: Electromagnetic Waves

Which of the following exert the smallest amount of radiation pressure?

A beam of unpolarized light with an intensity of 1000 W/m2 impinges on a set of two linear polarizers with their polarization axes at an angle θ\thetaθ relative to each other.If the light transmitted through this combination has an intensity of 250 W/m2,what is θ\thetaθ ?

Unpolarized light of intensity 200 W/m2 is incident on a polarizer A. Light leaving this polarizer is then incident on a polarizer B with its polarization axis oriented at 30 ∘\circ∘ with respect to that of A. What is the intensity of the light leaving polarizer B?

A parallel plate capacitor with radius 21 cm is connected in series with a 15-V battery.A switch is thrown which causes the capacitor to discharge through a 150- Ω\varOmegaΩ resistor.What is the displacement current between the plates at this time?

Which waves have the longest wavelength in the electromagnetic spectrum?

What is the distance between successive heating anti-nodes in a microwave oven's cavity? The microwave oven uses 1200 W and uses a frequency of 2.4 Gigahertz.

A focused 100 W spotlight delivers 50% of its light into a circle with a diameter of 50 cm.What is the average rms electric field in this illuminated area?

A green laser beam with a wavelength of 515 nm is transmitting a signal to a satellite.If it takes 1.0 ms for the signal to reach the satellite,how far away is the satellite?

Unpolarized light of intensity 100 mW/m2 passes through two filters.The first filter has an alignment of 30.0 degrees from the vertical and the second has an alignment of 80.0 degrees from the vertical.What is the intensity of the light that passes through the second filter?

An electric field of 100 V/m is directed outward from the plane of a circular area with radius 4.0 cm.If the electric field increases at a rate of 10 V/ms,determine the magnitude of the magnetic field at a radial distance 10.0 cm away from the center of the circular area.

The potential across a 10.0-mF capacitor is increasing at a rate of 120 V/s.What is the displacement current through the capacitor?

The amplitude of the electric field of an electromagnetic wave is 21 V/m.The amplitude of the magnetic field of the wave is

The amplitude of the electric field detected by an FM radio receiver is 400 µV/m.The intensity of the signal is

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Filters

A beam of unpolarized light with an intensity of 1000 W/m² impinges on a set of two linear polarizers with their polarization axes at an angle $\theta$ relative to each other.If the light transmitted through this combination has an intensity of 250 W/m²,what is $\theta$ ?

Unpolarized light of intensity 200 W/m² is incident on a polarizer A. Light leaving this polarizer is then incident on a polarizer B with its polarization axis oriented at 30^$\circ$ with respect to that of A. What is the intensity of the light leaving polarizer B?

A parallel plate capacitor with radius 21 cm is connected in series with a 15-V battery.A switch is thrown which causes the capacitor to discharge through a 150- $\varOmega$ resistor.What is the displacement current between the plates at this time?

Unpolarized light of intensity 100 mW/m² passes through two filters.The first filter has an alignment of 30.0 degrees from the vertical and the second has an alignment of 80.0 degrees from the vertical.What is the intensity of the light that passes through the second filter?