Question 1

A laser having with a spot 1.00 mm in diameter is shone perpendicularly on the center of a thin,perfectly reflecting circular (2.00 mm in diameter)aluminum plate mounted vertically on a flat piece of cork that floats on the surface of the water in a large beaker.The mass of this "sailboat" is 0.0550 g and it travels 3.00 mm in 50.0 s.Assuming that the laser power is constant in the region where the sailboat is located during the experiment,what is the power of the laser used in this demonstration? (Neglect air resistance and the viscosity of the water.)

Accepted Answer

A) 34.6 mW 
B) 25.2 mW 
C) 22.7 mW 
D) 19.8 mW 
E) 15.1 mW

Question 2

Multiwall Carbon Nanotubes (MWCN)can be synthesized by heating an SiC wafer by a high power laser such as a CO2 laser.If the diameter of a laser beam of 3-kW power and 10-µm wavelength is 3 mm,what force does the laser beam exert on the SiC wafer?

Accepted Answer

A) 9.8 * 10-4 N 
B) 3.12 * 10-5 N 
C) 1.00 * 10-5 N. 
D) 7.50 * 10-6 N

Question 3

The power of a light bulb is 100 W on a circular disk of radius 2 mm at a distance of 1m.What is the power on a 4-mm disk at a distance of 2 m from the same bulb?

Accepted Answer

A) 25 W 
B) 50 W 
C) 100 W 
D) 200 W 
E) 400 W

Question 4

A parallel plate capacitor with radius 21 cm is connected in series 15-V battery.A switch is thrown which causes the capacitor to discharge through a 150-$\varOmega$ resistor.What is the magnetic field 1.0 cm from the axis defined by the centers of the plates at this time?

Accepted Answer

A) 1.0 * 10-12 T 
B) 3.1 * 10-12 T 
C) 2.1 * 10-11 T 
D) 4.5 * 10-9 T 
E) You need to know the separation of the plates.

Question 5

The current flowing in a 20-cm long and 2-cm radius solenoid having 500 turns decreases from 3 A to 1 A in 0.1 seconds.Determine the magnitude of the induced electric field inside the solenoid 1-cm from its center.

Accepted Answer

A) 5 * 10-1 V/m 
B) 5 * 10-4 V/m 
C) 3 * 10-4 V/m 
D) 3 * 10-2 V/m

Question 6

A cell phone transmits 2.0 W of power at 380 MHz in a spherical pattern.What is the rms value of the electric field on the electron in the receiving antenna,located 3.0 km away?

Accepted Answer

A) 1.5 * 10S1U1P1-7S1S1P0 V/m 
B) 6.8 * 10S1U1P1-6S1S1P0 V/m 
C) 1.3 * 10S1U1P1-4S1S1P0 V/m 
D) 2.6 * 10S1U1P1-3S1S1P0 V/m 
E) 2.3 V/m

Question 7

The potential across a 10 mF capacitor is increasing at a constant rate.If the displacement current through the capacitor is 10.0 A,what is the rate at which the potential difference is increasing across the capacitor's plates.

Accepted Answer

A) 100 V/s 
B) 120 V/s 
C) 50 V/s 
D) None are correct.

Question 8

Laser light with an intensity of 40,000 W/m2 perpendicularly hits a black perfect absorber rectangular area of width W = 27 mm and height H = 35 mm.What is the force this laser exerts on the area?

Accepted Answer

A) 1.26 * 10-7 N 
B) 33.8 N 
C) 2.2 N 
D) 34.5 * 10-6 N 
E) 9.8 * 10-15 N

Question 9

The unit of the quantity $\varepsilon$0(d$\varPhi$E/dt)is

Accepted Answer

A) amperes. 
B) volts. 
C) ampere.meters. 
D) volt.meters.

Question 10

What creates magnetic fields?

Accepted Answer

A) moving charges 
B) changing electric fields 
C) Both A and B are correct. 
D) None are correct.

Question 11

What is the direction of the net force on the moving charge in figure shown?

Accepted Answer

A) into the page 
B) right 
C) out of the page 
D) left

Question 12

A laser beam is reflected back from a totally reflecting sail on a spacecraft that is 4.5 * 107 m from the source of the beam.How long after the beam is sent does it return to the source?

Accepted Answer

A) 100 ms 
B) 200 ms 
C) 150 ms 
D) 300 ms

Question 13

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.What is her total mass with equipment if her resulting acceleration is 1.6 * 10-9 m/s2 towards the shuttle?

Accepted Answer

A) 84 kg 
B) 119 kg 
C) 100 kg 
D) 110 kg 
E) 133 kg

Question 14

A 5-mW laser pointer has a beam diameter of 3 mm.What is the total electromagnetic energy in a 2.0 m length of this laser beam?

Accepted Answer

A) 2.3 * 10-16 J 
B) 4.7 * 10-16 J 
C) 1.7 * 10-11 J 
D) 3.3 * 10-11 J 
E) 5.0 * 10-3 J

Exam 31: Electromagnetic Waves

Multiwall Carbon Nanotubes (MWCN) can be synthesized by heating an SiC wafer by a high power laser such as a CO₂ laser.If the diameter of a laser beam of 3-kW power and 10-µm wavelength is 3 mm,what force does the laser beam exert on the SiC wafer?

The power of a light bulb is 100 W on a circular disk of radius 2 mm at a distance of 1m.What is the power on a 4-mm disk at a distance of 2 m from the same bulb?

A parallel plate capacitor with radius 21 cm is connected in series 15-V battery.A switch is thrown which causes the capacitor to discharge through a 150- $\varOmega$ resistor.What is the magnetic field 1.0 cm from the axis defined by the centers of the plates at this time?

The current flowing in a 20-cm long and 2-cm radius solenoid having 500 turns decreases from 3 A to 1 A in 0.1 seconds.Determine the magnitude of the induced electric field inside the solenoid 1-cm from its center.

A cell phone transmits 2.0 W of power at 380 MHz in a spherical pattern.What is the rms value of the electric field on the electron in the receiving antenna,located 3.0 km away?

The potential across a 10 mF capacitor is increasing at a constant rate.If the displacement current through the capacitor is 10.0 A,what is the rate at which the potential difference is increasing across the capacitor's plates.

Laser light with an intensity of 40,000 W/m² perpendicularly hits a black perfect absorber rectangular area of width W = 27 mm and height H = 35 mm.What is the force this laser exerts on the area?

The unit of the quantity $\varepsilon$ ₀(d $\varPhi$ _E/dt) is

What creates magnetic fields?

What is the direction of the net force on the moving charge in figure shown?

A laser beam is reflected back from a totally reflecting sail on a spacecraft that is 4.5 * 10⁷ m from the source of the beam.How long after the beam is sent does it return to the source?

A 5-mW laser pointer has a beam diameter of 3 mm.What is the total electromagnetic energy in a 2.0 m length of this laser beam?

Exam 31: Electromagnetic Waves

Multiwall Carbon Nanotubes (MWCN) can be synthesized by heating an SiC wafer by a high power laser such as a CO2 laser.If the diameter of a laser beam of 3-kW power and 10-µm wavelength is 3 mm,what force does the laser beam exert on the SiC wafer?

The power of a light bulb is 100 W on a circular disk of radius 2 mm at a distance of 1m.What is the power on a 4-mm disk at a distance of 2 m from the same bulb?

A parallel plate capacitor with radius 21 cm is connected in series 15-V battery.A switch is thrown which causes the capacitor to discharge through a 150- Ω\varOmegaΩ resistor.What is the magnetic field 1.0 cm from the axis defined by the centers of the plates at this time?

The current flowing in a 20-cm long and 2-cm radius solenoid having 500 turns decreases from 3 A to 1 A in 0.1 seconds.Determine the magnitude of the induced electric field inside the solenoid 1-cm from its center.

A cell phone transmits 2.0 W of power at 380 MHz in a spherical pattern.What is the rms value of the electric field on the electron in the receiving antenna,located 3.0 km away?

The potential across a 10 mF capacitor is increasing at a constant rate.If the displacement current through the capacitor is 10.0 A,what is the rate at which the potential difference is increasing across the capacitor's plates.

Laser light with an intensity of 40,000 W/m2 perpendicularly hits a black perfect absorber rectangular area of width W = 27 mm and height H = 35 mm.What is the force this laser exerts on the area?

The unit of the quantity ε\varepsilonε 0(d Φ\varPhiΦ E/dt) is

What creates magnetic fields?

What is the direction of the net force on the moving charge in figure shown?

A laser beam is reflected back from a totally reflecting sail on a spacecraft that is 4.5 * 107 m from the source of the beam.How long after the beam is sent does it return to the source?

A 5-mW laser pointer has a beam diameter of 3 mm.What is the total electromagnetic energy in a 2.0 m length of this laser beam?

Multiwall Carbon Nanotubes (MWCN) can be synthesized by heating an SiC wafer by a high power laser such as a CO₂ laser.If the diameter of a laser beam of 3-kW power and 10-µm wavelength is 3 mm,what force does the laser beam exert on the SiC wafer?

A parallel plate capacitor with radius 21 cm is connected in series 15-V battery.A switch is thrown which causes the capacitor to discharge through a 150- $\varOmega$ resistor.What is the magnetic field 1.0 cm from the axis defined by the centers of the plates at this time?

Laser light with an intensity of 40,000 W/m² perpendicularly hits a black perfect absorber rectangular area of width W = 27 mm and height H = 35 mm.What is the force this laser exerts on the area?

The unit of the quantity $\varepsilon$ ₀(d $\varPhi$ _E/dt) is

A laser beam is reflected back from a totally reflecting sail on a spacecraft that is 4.5 * 10⁷ m from the source of the beam.How long after the beam is sent does it return to the source?