Question 1

What is the frequency of the light emitted by atomic hydrogen with m = 8 and n = 12? (The Rydberg constant is R = 1.097 × 107 m-1, c = 3.00 × 108 m/s)

Accepted Answer

A)  2.86 × 1013 Hz 
B)  1.43 × 1013 Hz 
C)  7.46 × 1013 Hz 
D)  8.82 × 1013 Hz 
E)  1.05 × 1013 Hz 
A)  2.86 × 1013 Hz 
B)  1.43 × 1013 Hz 
C)  7.46 × 1013 Hz 
D)  8.82 × 1013 Hz 
E)  1.05 × 1013 Hz A

Question 2

At absolute temperature T, a black body radiates its peak intensity at wavelength λ. At absolute temperature 2T, what would be the wavelength of the peak intensity?

Accepted Answer

A)  16λ 
B)  2λ 
C)  λ 
D)  λ/2 
E)  λ/16 
A)  16λ 
B)  2λ 
C)  λ 
D)  λ/2 
E)  λ/16 D

Question 3

A perfectly black body at 100°C emits light of intensity I that has the strongest intensity near wavelength λ. The temperature of this body is now increased to 200°C.
(a) In terms of I, what is the intensity at which this hotter body radiates?
(b) In terms of λ, near what wavelength does light radiated from this hotter body have the strongest intensity?

Accepted Answer

(a) 2.6I 
(b) 0.80 λ

Question 4

An electric current through a tungsten filament maintains its temperature at 2800 K. Assume the tungsten filament behaves as an ideal radiator at that temperature. Near what wavelength does the filament emit the greatest power? (σ = 5.67 × 10-8 W/m2 ∙ K4, Wien displacement law constant is
2.9 × 10-3 m ∙ K)

Accepted Answer

A)  1000 nm 
B)  1200 nm 
C)  1400 nm 
D)  1600 nm 
E)  1800 nm 
A)  1000 nm 
B)  1200 nm 
C)  1400 nm 
D)  1600 nm 
E)  1800 nm

Question 5

A perfectly black sphere 18.0 cm in diameter is held at a temperature of 215°C. (σ = 5.670 × 10-8 W/m2 ∙ K4, Wien displacement law constant is 2.90 × 10-3 m ∙ K, h = 6.626 × 10-34 J ∙ s, c = 3.00 × 108 m/s)
(a) Near what wavelength does this sphere radiate most strongly?
(b) If all the radiated energy were at the wavelength found in part (a), how many photons would the sphere emit each second?

Accepted Answer

(a) 5.94 µ

Question 6

What is the wavelength of peak emission for a black body at 37°C? (c = 3.0 × 108 m/s, Wien displacement law constant is 2.9 × 10-3 m ∙ K, σ = 5.67 × 10-8 W/m2 ∙ K4)

Accepted Answer

A)  94 µm 
B)  9.4 µm 
C)  29 µm 
D)  7.8 µm 
E)  78 µm 
A)  94 µm 
B)  9.4 µm 
C)  29 µm 
D)  7.8 µm 
E)  78 µm

Question 7

In the vicinity of what frequency does an object with a temperature of 1000 K radiate the largest amount of power? (c = 3.00 × 108 m/s, Wien displacement law constant equals 2.90 × 10-3 m ∙ K,
Σ = 5.670 × 10-8 W/m2 ∙ K4)

Accepted Answer

A)  1.0 × 1014 Hz 
B)  8.0 × 1014 Hz 
C)  2.3 × 1014 Hz 
D)  6.7 × 1014 Hz 
E)  4.1 × 1014 Hz 
A)  1.0 × 1014 Hz 
B)  8.0 × 1014 Hz 
C)  2.3 × 1014 Hz 
D)  6.7 × 1014 Hz 
E)  4.1 × 1014 Hz

Question 8

An electric current through a tungsten filament maintains its temperature at 2800 K. Assume the tungsten filament behaves as an ideal radiator at that temperature. If the radiating area of the filament is 2.0 × 10-6 m2, at what rate does it radiate energy? (σ = 5.670 × 10-8 W/m2 ∙ K4, Wien displacement law constant is 2.90 × 10-3 m ∙ K)

Accepted Answer

A)  5.5 W 
B)  7.0 W 
C)  8.5 W 
D)  10 W 
E)  11.5 W 
A)  5.5 W 
B)  7.0 W 
C)  8.5 W 
D)  10 W 
E)  11.5 W

Exam 37: The Foundations of Modern Physics

What is the frequency of the light emitted by atomic hydrogen with m = 8 and n = 12? (The Rydberg constant is R = 1.097 × 107 m-1, c = 3.00 × 108 m/s)

At absolute temperature T, a black body radiates its peak intensity at wavelength λ. At absolute temperature 2T, what would be the wavelength of the peak intensity?

What is the wavelength of peak emission for a black body at 37°C? (c = 3.0 × 108 m/s, Wien displacement law constant is 2.9 × 10-3 m ∙ K, σ = 5.67 × 10-8 W/m2 ∙ K4)

In the vicinity of what frequency does an object with a temperature of 1000 K radiate the largest amount of power? (c = 3.00 × 108 m/s, Wien displacement law constant equals 2.90 × 10-3 m ∙ K, Σ = 5.670 × 10-8 W/m2 ∙ K4)

Concepts of Motion

Kinematics in One Dimension

Vectors and Coordinate Systems

Kinematics in Two Dimensions

Force and Motion

Dynamics I: Motion Along a Line

Newtons Third Law

Dynamics Ii: Motion in a Plane

Impulse and Momentum

Energy

Work

Rotation of a Rigid Body

Newtons Theory of Gravity

Oscillations

Fluids and Elasticity

A Macroscopic Description of Matter

Work, Heat, and the First Law of Thermodynamics

The Micromacro Connection

Heat Engines and Refrigerators

Traveling Waves

Superpositions

Wave Optics

Ray Optics

Optical Instruments

Electric Charges and Forces

The Electric Field

Gausss Law

The Electric Potential

Potential and Field

Current and Resistance

Fundamentals of Circuits

The Magnetic Field

Electromagnetic Induction

Electromagnetic Fields and Waves

Ac Circuits

Relativity

Quantization

Wave Functions and Uncertainty

One-Dimensional Quantum Mechanics

Atomic Physics

Nuclear Physics

Filters

What is the frequency of the light emitted by atomic hydrogen with m = 8 and n = 12? (The Rydberg constant is R = 1.097 × 10⁷ m^-1,^c= 3.00 × 10⁸ m/s)

What is the wavelength of peak emission for a black body at 37°C? (c = 3.0 × 10⁸ m/s, Wien displacement law constant is 2.9 × 10^-3 m ∙ K, σ = 5.67 × 10^-8 W/m² ∙ K⁴)

In the vicinity of what frequency does an object with a temperature of 1000 K radiate the largest amount of power? (c = 3.00 × 10⁸ m/s, Wien displacement law constant equals 2.90 × 10^-3 m ∙ K, Σ = 5.670 × 10^-8 W/m² ∙ K⁴)