ESCI10_Physics

A comprehensive set of Question-and-Answer flashcards covering key concepts from electromagnetism, waves, optics, and nuclear physics found in the notes.

What did Hans Christian Oersted discover about electricity and magnetism in 1820?

Electric currents create magnetic fields; a compass near a current-carrying wire deflected, showing a magnetic field is generated.

What is Ampere’s Law primarily about?

Quantifies the magnetic force generated by an electric current; parallel wires attract if currents flow in the same direction and repel if they flow in opposite directions.

What is Faraday’s key contribution to electromagnetism?

Electromagnetic induction: a changing magnetic field can produce an electric current; moving a magnet into a coil deflects a galvanometer, indicating induced current.

What did James Clerk Maxwell contribute to the theory of electromagnetism?

Maxwell’s equations describing the behavior and interaction of electric and magnetic fields; a changing electric field can produce a magnetic field even without current; unified electricity, magnetism, and light as EM waves.

What did Heinrich Hertz experimentally confirm?

The existence of electromagnetic waves; radio waves are a form of electromagnetic radiation, foundational for wireless communication.

What is the speed of electromagnetic waves in vacuum?

Approximately 3.00 x 10^8 meters per second.

What does the equation E = hf represent, and what is h?

The energy of a photon; E equals Planck’s constant times frequency. h = 6.63 x 10^-34 J·s.

How long does it take sunlight to reach Earth?

About 8 minutes.

State Snell’s Law.

n1 sin(theta1) = n2 sin(theta2), relating incident and refracted angles through refractive indices.

Using Snell’s Law, if light travels from air (n1 ≈ 1.00) into water (n2 ≈ 1.33) at theta1 = 40°, what is theta2 approximately?

sin(theta2) ≈ (n1/n2) sin(theta1) ≈ (1.00/1.33) sin(40°) ≈ 0.483, so theta2 ≈ 28.9°.

What is the energy of an x-ray photon with frequency 3 x 10^17 Hz?

E = hf ≈ (6.63 x 10^-34 J·s)(3 x 10^17 s^-1) ≈ 1.99 x 10^-16 J.

What are electromagnetic waves and where can they travel?

Waves produced by vibrating electric and magnetic fields; they can travel through vacuum and do not require a medium.

List the main segments of the electromagnetic spectrum in order from longest to shortest wavelength.

Radio waves, Microwaves, Infrared, Visible light, Ultraviolet, X-rays, Gamma rays.

What is a radiowave typically produced by and what is it used for?

Produced by oscillating electrons in an antenna; used to transmit sound and picture information over long distances.

What characterizes microwaves and their common uses?

Can penetrate the atmosphere; used for satellite communications and everyday cooking in microwave ovens.

What generates infrared radiation and what is a common use of infrared imaging?

All objects emit infrared radiation; thermal imaging detects temperature differences and is used in engineering and military contexts.

What is visible light, and how are solar PV cells typically constructed?

Visible light is the portion of the spectrum visible to the human eye; solar PV cells are often silicon-based and convert photon energy into electricity.

What produces ultraviolet radiation from the sun and what is a common tanning device application?

UV radiation from the sun; tanning beds use specific UVA/UVB blends to stimulate melanin production.

What is a key use of X-rays in science and medicine?

X-ray imaging and diagnostics; produced by high-energy electron interactions in an X-ray tube; can penetrate flesh but not bone.

What is gamma radiation and a major medical application?

Very high-energy photons emitted by radioactive materials or stars; used in radiotherapy to treat cancer and for sterilization of water.

What is radioactive decay and what factors influence it?

Decay governed by the strong nuclear force; unstable nuclei decay via alpha, beta, or gamma processes; isotopes have same proton number but different neutrons.

What is an isotope?

Atoms with the same atomic number (protons) but different numbers of neutrons.

Describe alpha decay.

Emission of an alpha particle (2 protons and 2 neutrons); nucleus loses mass and decreases atomic number by 2.

Describe beta decay (beta minus).

A neutron decays into a proton and an electron; the electron is ejected; increases atomic number by 1.

Describe beta decay (beta plus).

A proton decays into a neutron and a positron; the positron is ejected; decreases atomic number by 1.

Describe gamma decay.

Rearrangement of protons and neutrons in the nucleus with emission of gamma rays; no change in atomic number or mass.

What is the law of reflection?

The angle of incidence (thetai) equals the angle of reflection (thetar); incident ray, reflected ray, and normal lie in the same plane.

What is the difference between specular and diffuse reflection?

Specular reflection occurs on smooth surfaces (like mirrors); diffuse reflection occurs on rough surfaces (like paper).

What is the normal line in reflection geometry?

An imaginary line perpendicular to the reflecting surface at the point of incidence.

What are the typical properties of a plane mirror image?

Image size equals object size; image is virtual and located behind the mirror; left-right reversal; magnification is 1.

What are the primary features of concave mirrors?

Can produce real and inverted images or virtual and upright images depending on object distance from the mirror; focal length and center of curvature define image location.

What are the primary features of convex mirrors?

Always produce virtual, upright, diminished images located behind the mirror.

What are concave and convex lenses in terms of curvature and light bending?

Concave lenses are thinner in the middle with inward-curved surfaces; convex lenses are thicker in the middle with outward-curved surfaces; both bend light via refraction.

State the magnification formula for mirrors and lenses.

M = h' / h, where h' is image height and h is object height (also M = image distance / object distance in some contexts).

State the mirror/lens equation and its standard form.

1/f = 1/p + 1/q, where f is focal length, p is object distance, and q is image distance.

What is a rule of sign conventions described in the notes for f, q, and real vs virtual images?

f+ corresponds to concave (converging) elements; f- corresponds to convex (diverging); q+ indicates a real image (in front of the mirror or behind a lens), q- indicates a virtual image.

Name some common optical instruments listed in the notes.

Camera, Microscope, Telescope, Eyes, Pinholes, Periscope, Binoculars.

What are common vision defects and their corrective lenses?

Nearsightedness (myopia) corrected with concave lens; farsightedness (hyperopia) corrected with convex lens.

What are Fleming’s Right-Hand Rule and Left-Hand Rule used for?

Right-Hand Rule: generator (induced current direction from magnetic field and motion); Left-Hand Rule: motor (motion from magnetic field and current).

What are the essential components of a simple electric generator?

Armature (rotating conductor), slip rings, brushes; magnets providing the magnetic field.

What are the essential components of a simple electric motor?

Armature, commutator, brushes, and torque; magnets providing the magnetic field; the commutator reverses current to sustain rotation.

What does a galvanometer measure?

The magnitude and direction of current produced by a generator or in a circuit.

What is an electromagnet and how is its strength increased?

A magnet whose magnetic field can be switched on/off; a solenoid with a core; strength increases with more turns and a stronger core.

What is magnetic flux?

A measure of the total magnetic field passing through a given surface.