Physics Lecture Notes Flashcards

These flashcards cover key concepts and definitions from physics lecture notes.

What is a non-polar molecule?

A molecule with no permanent dipole moment.

What is a conductor?

A material where some electrons can move freely.

What is Coulomb's Law?

It describes the force exerted by one charge on another, inversely proportional to the square of the distance between them.

What is the law of conservation of charge?

The total electric charge in an isolated system remains constant.

What does an electric field (E) do?

Exerts forces on other charges.

What constitutes a dipole moment?

A measure of the separation of positive and negative charges in a system.

What is the unit of electric charge?

Coulomb (C).

What do electric field lines indicate?

The magnitude and direction of an electric field.

What describes the torque exerted on a dipole in an electric field?

A dipole tends to align itself with the direction of the external electric field.

What is electric flux?

The number of electric field lines passing through a given surface.

What does Gauss's Law state?

The net number of electric field lines out of any closed surface is proportional to the net charge enclosed by that surface.

What is electric potential energy (U)?

The energy a charged object possesses because of its position in an electric field.

What unit is used for electric potential?

Volts (V).

What is capacitance?

The ratio of the electric charge stored to the potential difference (voltage) across a capacitor.

What is the SI unit of capacitance?

Farad (F).

What does Kirchhoff's loop rule state about electrical circuits?

The sum of the potential differences around any closed loop in a circuit must be zero.

What is a junction in an electric circuit?

A point where a wire divides into two or more wires.

What is resistivity?

A material property that quantifies how strongly a material opposes the flow of electric current.

What is unique about voltage in a parallel circuit?

The voltage is the same across all components.

What is the definition of a magnetic field?

A region around a magnetic material or a moving electric charge within which the force of magnetism acts.

What is the magnetic dipole moment?

A measure of the strength of a magnetic source.

What is Lenz's Law?

The induced emf will always work to oppose the change in current that produced it.

What is the Hall Effect?

The development of a voltage across a conductor when it is placed in a magnetic field and a current flows through it.

What is Faraday's Law?

The induced emf in any closed circuit is equal to the rate of change of the magnetic flux through the circuit.

What does a generator do?

Produces current by converting mechanical energy into electrical energy.

What equation describes electromagnetic waves?

The wave equation that relates electric (E) and magnetic (B) fields.

What is the speed of light?

Approximately 3 x 10^8 m/s.

What is the Doppler Effect?

The change in frequency or wavelength of a wave in relation to an observer who is moving relative to the wave source.

What is polarization of light?

When light waves oscillate in parallel planes.

What is the relationship described by Snell's Law?

The relationship between the angles of incidence and refraction when light passes from one medium to another.

What is the principle behind lenses?

Lenses bend light rays to converge or diverge them to form images.

What is the focal length of a lens?

The distance from the lens to the focal point.

What does the term 'virtual image' refer to?

An image formed by rays that appear to diverge from a point but do not actually converge.

What defines a concave mirror?

A mirror that curves inward, converging light to a focal point.

What is the equation for the electric field inside a parallel plate capacitor?

E = V/d, where V is voltage and d is the distance between plates.

What is the role of dielectrics in capacitors?

Increase capacitance by storing additional charge.

What are the characteristics of electric charges?

They can be positive, negative, or neutral; they exert forces on each other and can be transferred.

What unit measures the intensity of magnetism?

Tesla (T).

Define torque in relation to magnetic fields.

The force exerted on a loop of wire in a magnetic field that causes it to rotate.

What happens when light hits a surface at Brewster's angle?

Light reflected at this angle is completely polarized.

What is an ammeter?

A device used to measure current in a circuit.

What is a voltmeter?

A device used to measure voltage between two points.

How does current flow in a series circuit?

The same current flows through all components.

What is electric current?

The rate of flow of electric charge.

What is an inductor?

A component in an electrical circuit that stores energy in a magnetic field.

Describe the behavior of electric fields due to point charges.

Electric fields radiate outward from positive charges and inward toward negative charges.

What is the difference between permanent and induced dipoles?

Permanent dipoles have a constant dipole moment, while induced dipoles arise from external electric fields.

What is the importance of the Coulomb's constant?

It quantifies the strength of the electrostatic force between charges.

What is the term for energy stored per unit volume in an electric field?

Electric field energy density.

What factor affects the strength of an electric field?

The amount of charge and the distance from the charge.

Define a solenoid.

A coil of wire wound in a spiral shape, generating a magnetic field when an electric current passes through.

What does the term 'equivalent capacitance' refer to?

The total capacitance of a combination of capacitors.

What is the function of a shunt resistor?

Used to measure current by allowing a known amount of current to bypass the measuring device.

What is the significance of Kirchhoff's current law?

Total current entering a junction must equal total current leaving the junction.

Define energy density in magnetic fields.

The amount of energy stored per unit volume in a magnetic field.

What is the magnetic field outside a current-carrying conductor?

It is circular and decreases with distance from the wire.

What role do resistors play in circuits?

Limit the flow of current and drop voltage.

What does the electromagnetic spectrum consist of?

Different types of electromagnetic radiation, including visible light, radio waves, and X-rays.

What is the phenomenon of diffraction?

The bending of waves around obstacles or through openings.

What defines the angle of incidence?

The angle between the incident ray and the normal to the surface where it strikes.

What is the relationship between frequency and wavelength?

They are inversely proportional to each other.

Define inductance.

The property of a coil that opposes changes in current.

What is Maxwell's equation about electromagnetic waves?

It states that changing electric fields generate magnetic fields and vice versa.

What defines a ferromagnet?

A material that can be magnetized and retains its magnetism.

What does a polaroid filter do?

Allows only light waves that oscillate in a certain direction to pass through.

Define electric potential difference.

The work done per unit charge to move a charge between two points in an electric field.

What is meant by the term 'grounding' in electrical circuits?

Connecting a circuit to the earth to prevent buildup of voltages.

What is the formula for gravitational potential energy?

U = mgh, where m is mass, g is acceleration due to gravity, and h is height.

What are the characteristics of insulators?

Materials that do not allow electric charges to flow freely.

What is the purpose of a capacitor in a circuit?

To store electrical energy temporarily.

What principle describes how light behaves when it enters a denser medium?

Refraction occurs, changing the light's angle.

What is an alternating current (AC)?

A type of current that periodically reverses direction.

What does Ohm's law state?

Voltage equals current times resistance (V = IR).

What is the function of electric field lines in a diagram?

They visually represent the direction and strength of electric fields.

What occurs during electromagnetic induction?

An induced emf is created in a circuit due to the change in magnetic flux.

Define the term 'photoelectric effect.'

The emission of electrons from a material when light is shone on it.

What factors determine the resistance of a conductor?

Length, cross-sectional area, and resistivity of the material.

Describe a photon.

A quantum of electromagnetic radiation, representing a particle of light.

What does the law of reflection state?

The angle of incidence is equal to the angle of reflection.

What is the role of an electrolyte in a battery?

To allow the flow of ions, facilitating chemical reactions that generate electricity.

What is energy storage in capacitors related to?

Stored energy is related to the voltage and capacitance.

How do you calculate the electric field (E) between the plates of a parallel plate capacitor?

Use the formula E = V/d, where V is the voltage across the plates and d is the distance between the plates.

What is the total capacitance of two capacitors, C1 and C2, connected in series?

Use the formula 1/C_total = 1/C1 + 1/C2.

How do you find the potential energy (U) stored in a capacitor?

Use the formula U = (1/2)CV^2, where C is the capacitance and V is the voltage.

If a battery applies a voltage of 12V across a resistor of 4Ω, what is the current flowing through the circuit?

Use Ohm's law: I = V/R, where I is the current, V is the voltage, and R is the resistance. Here, I = 12V/4Ω = 3A.

How is resistance (R) calculated for a cylindrical conductor?

Use the formula R = ρ(L/A), where ρ is the resistivity, L is the length, and A is the cross-sectional area of the conductor.

What is the relationship between frequency (f) and wavelength (λ) of electromagnetic waves?

Use the formula c = fλ, where c is the speed of light.

How do you describe the induced emf (ε) in a loop of wire when a magnetic field changes?

Use Faraday's Law: ε = -dΦ/dt, where Φ is the magnetic flux.

If the magnetic field strength (B) around a current-carrying wire is required, which formula would you use?

Use B = (μ₀/4π)(2I/r), where μ₀ is the permeability of free space, I is the current, and r is the distance from the wire.

What do you use to calculate the torque (τ) on a magnetic dipole in an external magnetic field (B)?

Use the formula τ = mBsin(θ), where m is the magnetic moment, B is the magnetic field strength, and θ is the angle between them.

How is the energy density (u) in an electric field (E) calculated?

Use the formula u = (1/2)εE², where ε is the permittivity of the medium.

What is the formula for calculating the current (I) in a circuit given voltage (V) and resistance (R)?

Use Ohm's Law: I = V/R.

How do you calculate the power (P) consumed by a resistor in an electric circuit?

Use the formula P = VI, where V is the voltage and I is the current.

What formula gives the voltage (V) across a capacitor when charge (Q) and capacitance (C) are known?

Use the formula V = Q/C.

What is the formula to calculate electrical power in terms of resistance and current?

Use the formula P = I²R.

How do you calculate the impedance (Z) in an AC circuit with resistance (R) and reactance (X)?

Use Z = √(R² + X²).

What formula do you use to find the gravitational potential energy (U) of an object at height (h)?

Use U = mgh, where m is mass, g is acceleration due to gravity, and h is height.

How is the wavelength (λ) of a wave calculated if you know the speed (v) and frequency (f)?

Use the formula v = fλ, which rearranges to λ = v/f.

What is the formula for calculating the induced voltage (emf) in a coil when the magnetic flux changes?

Use Faraday's Law: ε = -dΦ/dt.

How do you calculate the kinetic energy (KE) of an object?

Use the formula KE = (1/2)mv², where m is mass and v is velocity.