510 marks

Magnetic effects of current and magnetism

This chapter deals with the magnetic field due to moving charges and currents, along with magnetic properties of materials.

30 Topics

45h prep

3.3% subject weight

30 Topics

Biot - Savart law and its application to current carrying circular loop

2m3/10

📌 Key FormuladB = (μ₀/4π) I dl × r / r³, B at center of loop = μ₀I/(2R)

Ampere's law and its applications to infinitely long current carrying straight wire and solenoid

2m3/10

📌 Key Formula∮ B·dl = μ₀ I_enclosed. For wire: B = μ₀I/(2πr), solenoid: B = μ₀nI

Force on a moving charge in uniform magnetic and electric fields

2m3/10

📌 Key FormulaF_m = q v × B, F_e = qE, Lorentz force F = q(E + v × B)

Cyclotron

2m2/10

📌 Key Formulaf = qB/(2πm) (cyclotron frequency)

Force on a current-carrying conductor in a uniform magnetic field

2m2/10

📌 Key FormulaF = I L × B

The force between two parallel current carrying conductors definition of ampere

2m2/10

📌 Key FormulaF/L = μ₀ I₁ I₂/(2πd), definition of ampere based on this.

Torque experienced by a current loop in a uniform magnetic field

2m3/10

📌 Key Formulaτ = N I A × B, magnetic moment m = N I A, τ = m × B

Moving coil galvanometer and its applications

2m2/10

📌 Key FormulaI = (k/NAB) θ, k is torsional constant.

Sensitivity Of Moving Coil Galvanometer

2m3/10

📌 Key FormulaCurrent sensitivity = θ/I = NAB/k, voltage sensitivity = θ/V = NAB/(kR)

Conversion Of Galvanometer To Ammeter

2m3/10

📌 Key FormulaShunt resistance S = I_g G / (I - I_g)

Conversion Of Galvanometer To Voltmeter

2m3/10

📌 Key FormulaSeries resistance R = V/I_g - G

Current loop as a magnetic dipole and its magnetic dipole moment

2m2/10

📌 Key Formulam = N I A, direction from right-hand rule.

Bar magnet as an equivalent solenoid

2m2/10

📌 Key FormulaMagnetic field similar to solenoid.

Magnetic field lines

2m1/10

📌 Key FormulaContinuous closed loops, from N to S outside magnet.

Earth's magnetic field and magnetic elements

2m1/10

📌 Key FormulaDeclination, dip, horizontal component.

Diamagnetism, Paramagnetism and Ferromagnetism substances

2m1/10

📌 Key FormulaDiamagnetic: weak repulsion, Paramagnetic: weak attraction, Ferromagnetic: strong attraction.

Magnetic susceptibility and permeability

2m2/10

📌 Key Formulaχ_m = μ_r - 1, μ = μ₀μ_r

Hysteresis

2m2/10

📌 Key FormulaLag in magnetization vs. magnetizing field, retentivity, coercivity.

Electromagnets and permanent magnets

2m1/10

📌 Key FormulaElectromagnets use soft iron (low retentivity), permanent magnets use hard steel (high retentivity).

Wave motion (plane waves only)

2m1/10

📌 Key FormulaDisturbance propagation.

Longitudinal and transverse waves

2m1/10

📌 Key FormulaLongitudinal: particle displacement along wave direction. Transverse: perpendicular.

Principle of superposition of waves

2m2/10

📌 Key Formulay_net = y₁ + y₂

Progressive waves

2m3/10

📌 Key Formulay = A sin(ωt - kx + φ)

Stationary waves

2m3/10

📌 Key FormulaFormed by superposition of two identical waves traveling in opposite directions.

Standing waves in strings and organ pipes

2m4/10

📌 Key FormulaNodes and antinodes, frequency f = nv/(2L) for string, f = nv/(4L) for closed pipe, etc.

Resonance

2m2/10

📌 Key FormulaLarge amplitude when driving frequency equals natural frequency.

Beats

2m2/10

📌 Key FormulaBeat frequency f_beat = |f₁ - f₂|

Doppler Effect in sound

2m4/10

📌 Key Formulaf' = f (v ± v₀)/(v ∓ v_s)

Speed of sound in gases

2m3/10

📌 Key Formulav = √(γP/ρ) = √(γRT/M)

Simple harmonic motion (S.H.M.) and its equation

2m3/10

📌 Key FormulaF = -kx, a = -ω²x, x = A sin(ωt + φ)

510 marks

Magnetic effects of current and magnetism

This chapter deals with the magnetic field due to moving charges and currents, along with magnetic properties of materials.

30 Topics

45h prep

3.3% subject weight

30 Topics

Biot - Savart law and its application to current carrying circular loop

2m3/10

📌 Key FormuladB = (μ₀/4π) I dl × r / r³, B at center of loop = μ₀I/(2R)

Ampere's law and its applications to infinitely long current carrying straight wire and solenoid

2m3/10

📌 Key Formula∮ B·dl = μ₀ I_enclosed. For wire: B = μ₀I/(2πr), solenoid: B = μ₀nI

Force on a moving charge in uniform magnetic and electric fields

2m3/10

📌 Key FormulaF_m = q v × B, F_e = qE, Lorentz force F = q(E + v × B)

Cyclotron

2m2/10

📌 Key Formulaf = qB/(2πm) (cyclotron frequency)

Force on a current-carrying conductor in a uniform magnetic field

2m2/10

📌 Key FormulaF = I L × B

The force between two parallel current carrying conductors definition of ampere

2m2/10

📌 Key FormulaF/L = μ₀ I₁ I₂/(2πd), definition of ampere based on this.

Torque experienced by a current loop in a uniform magnetic field

2m3/10

📌 Key Formulaτ = N I A × B, magnetic moment m = N I A, τ = m × B

Moving coil galvanometer and its applications

2m2/10

📌 Key FormulaI = (k/NAB) θ, k is torsional constant.

Sensitivity Of Moving Coil Galvanometer

2m3/10

📌 Key FormulaCurrent sensitivity = θ/I = NAB/k, voltage sensitivity = θ/V = NAB/(kR)

Conversion Of Galvanometer To Ammeter

2m3/10

📌 Key FormulaShunt resistance S = I_g G / (I - I_g)

Conversion Of Galvanometer To Voltmeter

2m3/10

📌 Key FormulaSeries resistance R = V/I_g - G

Current loop as a magnetic dipole and its magnetic dipole moment

2m2/10

📌 Key Formulam = N I A, direction from right-hand rule.

Bar magnet as an equivalent solenoid

2m2/10

📌 Key FormulaMagnetic field similar to solenoid.

Magnetic field lines

2m1/10

📌 Key FormulaContinuous closed loops, from N to S outside magnet.

Earth's magnetic field and magnetic elements

2m1/10

📌 Key FormulaDeclination, dip, horizontal component.

Diamagnetism, Paramagnetism and Ferromagnetism substances

2m1/10

📌 Key FormulaDiamagnetic: weak repulsion, Paramagnetic: weak attraction, Ferromagnetic: strong attraction.

Magnetic susceptibility and permeability

2m2/10

📌 Key Formulaχ_m = μ_r - 1, μ = μ₀μ_r

Hysteresis

2m2/10

📌 Key FormulaLag in magnetization vs. magnetizing field, retentivity, coercivity.

Electromagnets and permanent magnets

2m1/10

📌 Key FormulaElectromagnets use soft iron (low retentivity), permanent magnets use hard steel (high retentivity).

Wave motion (plane waves only)

2m1/10

📌 Key FormulaDisturbance propagation.

Longitudinal and transverse waves

2m1/10

📌 Key FormulaLongitudinal: particle displacement along wave direction. Transverse: perpendicular.

Principle of superposition of waves

2m2/10

📌 Key Formulay_net = y₁ + y₂

Progressive waves

2m3/10

📌 Key Formulay = A sin(ωt - kx + φ)

Stationary waves

2m3/10

📌 Key FormulaFormed by superposition of two identical waves traveling in opposite directions.

Standing waves in strings and organ pipes

2m4/10

📌 Key FormulaNodes and antinodes, frequency f = nv/(2L) for string, f = nv/(4L) for closed pipe, etc.

Resonance

2m2/10

📌 Key FormulaLarge amplitude when driving frequency equals natural frequency.

Beats

2m2/10

📌 Key FormulaBeat frequency f_beat = |f₁ - f₂|

Doppler Effect in sound

2m4/10

📌 Key Formulaf' = f (v ± v₀)/(v ∓ v_s)

Speed of sound in gases

2m3/10

📌 Key Formulav = √(γP/ρ) = √(γRT/M)

Simple harmonic motion (S.H.M.) and its equation

2m3/10

📌 Key FormulaF = -kx, a = -ω²x, x = A sin(ωt + φ)