# 44 Lecture

## PHY101

### Midterm & Final Term Short Notes

## Matter as Waves

Matter can exhibit both particle-like and wave-like behaviors, which is a fundamental concept in modern physics.

**Important Mcq's**

Midterm & Finalterm Prepration

Past papers included

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W**hat is the de Broglie wavelength of an electron with a velocity of 1.5 x 10^6 m/s?**

a. 0.253 nm

b. 2.53 nm

c. 25.3 nm

d. 253 nm

**Answer: a. 0.253 nm**

**Which of the following phenomena demonstrates the wave-like behavior of matter?**

a. Photoelectric effect

b. Compton scattering

c. Diffraction

d. None of the above

**Answer: c. Diffraction**

**Which equation is used to calculate the de Broglie wavelength of a particle?**

a. ? = h/mv

b. ? = h/mc

c. ? = h?

d. ? = hc/?

**Answer: a. ? = h/mv**

**Which of the following particles has the smallest de Broglie wavelength?**

a. A proton with a velocity of 10^6 m/s

b. An electron with a velocity of 10^7 m/s

c. A neutron with a velocity of 10^5 m/s

d. All particles have the same de Broglie wavelength.

**Answer: b. An electron with a velocity of 10^7 m/s**

**In which experiment did electrons exhibit interference patterns like those of waves?**

a. The photoelectric effect

b. The Compton effect

c. The double-slit experiment

d. The Stern-Gerlach experiment

**Answer: c. The double-slit experiment**

**Which of the following is an example of a particle that exhibits wave-like behavior?**

a. A proton

b. A photon

c. An electron

d. All of the above

**Answer: d. All of the above**

**The momentum of a particle is related to its de Broglie wavelength by which equation?**

a. p = h/?

b. ? = h/p

c. p = mc

d. ? = c/p

**Answer: b. ? = h/p**

**Which of the following is NOT an example of wave-particle duality?**

a. Electrons behaving like waves in a double-slit experiment

b. Photons behaving like particles in the photoelectric effect

c. Atoms behaving like waves in a diffraction experiment

d. None of the above

**Answer: d. None of the above**

**The uncertainty principle relates the uncertainty in a particle's position to the uncertainty in its:**

a. Momentum

b. Energy

c. Velocity

d. All of the above

**Answer: a. Momentum**

**Which of the following is a consequence of wave-particle duality?**

a. The Heisenberg uncertainty principle

b. The Bohr model of the atom

c. The law of conservation of energy

d. None of the above

**Answer: a. The Heisenberg uncertainty principle**

**Subjective Short Notes**

Midterm & Finalterm Prepration

Past papers included

Download PDF
**What is the de Broglie wavelength of a particle of mass m and velocity v?**

**Answer: **The de Broglie wavelength is given by ? = h/mv, where h is Planck's constant.

**What is the significance of the de Broglie wavelength?**

**Answer:** The de Broglie wavelength is significant because it shows that matter has wave-like properties, just like light. This wave-particle duality is a fundamental concept in quantum mechanics.

**What is the Heisenberg uncertainty principle?**

**Answer: **The Heisenberg uncertainty principle states that it is impossible to simultaneously determine the exact position and momentum of a particle. The more accurately we know one of these properties, the less accurately we can know the other.

**What is wave function collapse?**

**Answer:** Wave function collapse is the phenomenon where a quantum system that is in a superposition of states collapses into a definite state when it is measured or observed.

**What is the double-slit experiment?**

**Answer: **The double-slit experiment is a classic experiment in physics that demonstrates the wave-like nature of matter. In this experiment, a beam of particles, such as electrons, is directed at a screen with two slits. The resulting interference pattern on a detector behind the slits shows that the particles exhibit wave-like behavior.

**What is the Schrödinger equation?**

**Answer: **The Schrödinger equation is the fundamental equation of quantum mechanics that describes the time evolution of a quantum state. It is a differential equation that relates the wave function of a system to its energy.

**What is the wave function of a particle?**

**Answer: **The wave function of a particle is a mathematical function that describes the probability amplitude of finding the particle in a particular state or location.

**What is a probability density function?**

**Answer:** A probability density function is a mathematical function that describes the probability density of a particle being found in a particular region of space. It is related to the square of the wave function.

**What is quantum tunneling?**

**Answer:** Quantum tunneling is the phenomenon where a particle can pass through a barrier that it would not be able to pass through according to classical physics. This is due to the wave-like nature of matter, which allows it to "tunnel" through the barrier.

**What is an electron microscope?**

**Answer: **An electron microscope is a type of microscope that uses a beam of electrons instead of light to image samples. Since electrons have a much smaller wavelength than visible light, electron microscopes can achieve much higher resolution than optical microscopes.