Q: A photon has energy $$E = 3.0 \times 10$$^{-19}$$\ \mathrm{J}. $$What is its frequency? (Planck’s constant $$h = 6.63 \times 10$$^{-34}$$\ \mathrm{J \cdot s})$$

$$f = 4.5 \times 10$$^{14}$$\ \mathrm{Hz}$$

Question 1

Which of the following best describes the outcome and significance of the Michelson-Morley experiment?

Accepted Answer

It showed that the speed of light is constant in all inertial frames, leading to the downfall of the ether theory.

Question 2

A beam of monochromatic light passes through two closely spaced slits and forms an interference pattern on a screen. Which of the following changes would increase the distance between adjacent bright fringes?

Accepted Answer

Increasing the wavelength of the light.

Question 3

Which equation correctly expresses the condition for constructive interference in Young’s double-slit experiment?

Accepted Answer

$$d \sin 	heta = m \lambda$$

Question 4

A lens forms a real, inverted image of an object placed 30 cm from the lens. The image is formed 60 cm on the other side of the lens. What is the focal length of the lens?

Accepted Answer

$$f = 20\ \mathrm{cm}$$

Question 5

Which of the following statements about the photoelectric effect is correct?

Accepted Answer

Electrons are emitted only if the frequency of incident light exceeds a threshold value.

Question 6

A spaceship moves at $$0.8c$$ relative to Earth. According to special relativity, what is the Lorentz factor $$\gamma$$ for this speed?

Accepted Answer

$$\gamma = 1.67$$

Question 7

Which of the following best explains why blackbody radiation could not be explained by classical physics?

Accepted Answer

Classical physics predicted infinite energy emission at short wavelengths (ultraviolet catastrophe).

Question 8

Which formula gives the energy of a photon according to Planck’s hypothesis?

Accepted Answer

$$E = h f$$

Question 9

In the Compton effect, X-rays are scattered by electrons in a material. Which of the following is observed?

Accepted Answer

The scattered X-rays have a longer wavelength than the incident X-rays.

Question 10

According to Bohr’s model of the atom, which of the following is true about electron orbits?

Accepted Answer

Electrons occupy only certain allowed orbits with quantized angular momentum.

Question 11

Which equation represents the de Broglie wavelength of a particle with momentum $$p$$?

Accepted Answer

$$\lambda = \frac{h}{p}$$

Question 12

A radioactive isotope has a half-life of 10 years. What fraction of the original sample remains after 30 years?

Accepted Answer

$$\frac{1}{8}$$

Question 13

Which of the following is NOT a fundamental force in nature?

Accepted Answer

Frictional force

Question 14

Which statement best describes the uncertainty principle?

Accepted Answer

It is impossible to simultaneously know the exact position and momentum of a particle.

Question 15

Which of the following is a consequence of the Big Bang theory?

Accepted Answer

The universe is expanding from an initial hot, dense state.

Question 16

A beam of unpolarized light passes through a polarizer. What is the intensity of the transmitted light compared to the incident intensity?

Accepted Answer

$$I = \frac{1}{2} I_0$

Question 17

Which of the following best describes the role of Young’s double-slit experiment in the debate between wave and particle theories of light?

Accepted Answer

It provided strong evidence for the wave nature of light through the observation of interference patterns.

Question 18

A photon has energy $$E = 3.0 	imes 10$$^{-19}$$\ \mathrm{J}. $$What is its frequency? (Planck’s constant $$h = 6.63 	imes 10$$^{-34}$$\ \mathrm{J \cdot s})$$

Accepted Answer

$$f = 4.5 	imes 10$$^{14}$$\ \mathrm{Hz}$$

Question 19

Which of the following is a property of elementary particles according to the Standard Model?

Accepted Answer

Quarks combine to form protons and neutrons.

Question 20

A gamma ray photon strikes a stationary electron and scatters at an angle. Which conservation law is essential for analyzing the Compton effect?

Accepted Answer

Conservation of energy and momentum

Physics 206: Waves & Modern Physics – Course Outline and Study Guide

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