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Chapter 1 - Electric Current, Ohms Law and Kirchhoffs Laws

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Chapter 2 - Magnetic Effects of Electric Current and Measuring Instruments

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Chapter 3 - Electromagnetic Induction and AC Dynamo and Transformer

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Chapter 4 - Alternating Current AC Circuits

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Chapter 5 - Dual Nature of Wave and Particle

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Chapter 6 - Atomic Spectra and X-Rays

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Chapter 7 - Lasers and Principles

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Chapter 8 - Modern Electronics and Semiconductors

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Quiz

Lesson 1: Laser Physics, Population Inversion and the Helium-Neon Laser — Picture questions (exam style)

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  • Questions count: 10
  • Passing grade: 60%
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1.
Which statement about the laser shown is NOT correct?
Which statement about the laser shown is NOT correct?
in He–Ne energy passes from helium to neon by collisions
in He–Ne the lasing transition is in helium
the front cavity mirror is partially reflecting
a metastable level lengthens the excited lifetime
2.
Laser 1: 5 mW, 1064 nm, beam 2 mm; laser 2: 5 mW, 405 nm, beam 2 mm. (N = photons per s, I = beam intensity.) Which option is correct?
Laser 1: 5 mW, 1064 nm, beam 2 mm; laser 2: 5 mW, 405 nm, beam 2 mm. (N = photons per s, I = beam intensity.) Which option is correct?
N₁ : N₂ = 0.381, I₁ : I₂ = 2
N₁ : N₂ = 0.381, I₁ : I₂ = 1
N₁ : N₂ = 1, I₁ : I₂ = 1
N₁ : N₂ = 2.63, I₁ : I₂ = 1
3.
A 2.00 mW laser beam has diameter 1.00 mm. Find its intensity.
A 2.00 mW laser beam has diameter 1.00 mm. Find its intensity.
2550 W m−2
2000 W m−2
637 W m−2
8.00 W m−2
4.
A laser beam is 5.00 mm wide at the exit with divergence 2.00 mrad. What is the spot diameter 50.0 m away (as shown)?
A laser beam is 5.00 mm wide at the exit with divergence 2.00 mrad. What is the spot diameter 50.0 m away (as shown)?
0.100 m
0.205 m
0.105 m
0.0550 m
5.
A 10.0 mW laser beam has diameter 4.00 mm. Find its intensity.
A 10.0 mW laser beam has diameter 4.00 mm. Find its intensity.
625 W m−2
10.0 W m−2
199 W m−2
796 W m−2
6.
A 4.00 mW laser beam is fully absorbed by a surface. Find the force on it.
A 4.00 mW laser beam is fully absorbed by a surface. Find the force on it.
1.33×10−11 N
2.67×10−11 N
2.71×107 N
1.20×106 N
7.
A 0.500 mW laser beam is fully absorbed by a surface. Find the force on it.
A 0.500 mW laser beam is fully absorbed by a surface. Find the force on it.
1.50×105 N
1.67×10−12 N
4.31×106 N
3.33×10−12 N
8.
A 20.0 mW laser beam is fully absorbed by a surface. Find the force on it.
A 20.0 mW laser beam is fully absorbed by a surface. Find the force on it.
6.00×106 N
6.67×10−11 N
1.33×10−10 N
3.57×108 N
9.
A 4.00 mW laser beam has diameter 4.00 mm. Find its intensity.
A 4.00 mW laser beam has diameter 4.00 mm. Find its intensity.
79.6 W m−2
318 W m−2
4.00 W m−2
250 W m−2
10.
Which statement about the laser shown is NOT correct?
Which statement about the laser shown is NOT correct?
stimulated emission gives a photon with the same phase, frequency and direction
the front cavity mirror is partially reflecting
in He–Ne the lasing transition is in helium
population inversion is needed for amplification
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