# AP Inter 2nd Year Physics Notes Chapter 7 Moving Charges and Magnetism

Students can go through AP Inter 2nd Year Physics Notes 7th Lesson Moving Charges and Magnetism will help students in revising the entire concepts quickly.

## AP Inter 2nd Year Physics Notes 7th Lesson Moving Charges and Magnetism

→ A magnetic field always associated with a current.

→ Biot – Savarts law is valid for a symmetrical current distribution.

→ The magnetic field produced by a circular current carrying conductor is non-uniform but for practical purposes it is considered to be uniform at its centre.

→ Charges at rest produces electrostatic interaction where as charges in motion produce magnetic interaction.

→ Magnetic force is much smaller than the electric force.

→ An oscillating and an accelerated charge produces electro magnetic waves.

→ The force experienced by a charged particle moving in space where both electric and magnetic fields exist is called Lorentz force.

→ Ampere’s circuital law states that the line integral of magnetic field (B) around any closed path is equal to μ0 times the total current (i) in the closed circuit.
$$\oint \overrightarrow{\mathrm{B}} \cdot \overrightarrow{\mathrm{d}} l=\mu_0 \mathrm{i}$$

→ The Television uses the solenoid to generate needed magnetic fields.

→ The Toroid is a hollow circular ring made of insulating material on which a large number of turns of a wire are closely wound.

→ Biot – Savart s law can be represented as $$\overrightarrow{\mathrm{dB}}=\frac{\mu_0}{4 \pi} \cdot \frac{\mathrm{id} l \sin \theta}{\mathrm{r}^2}=\frac{\mu_0}{4 \pi} \cdot \frac{\mathrm{i} \overrightarrow{\mathrm{d} l} \times \overrightarrow{\mathrm{r}}}{\mathrm{r}^3}$$

→ Two parallel wires carrying current in the same direction attract each other and current in opposite direction repel each other.

→ A cyclotron cannot accelerate electrons and neutrons.

→ Ammeter is always connected in series in the circuit.

→ Voltmeter is always connected in parallel in the circuit.

→ An ideal Ammeter has zero resistance.

→ An ideal Voltmeter has infinite resistance.

→ A planar loop carrying a current i having N closely wound turns and an area A possesses a magnetic moment m.
m = NiA

→ An electron moving around the central neucleous has a magnetic moment μl = $$\frac{\mathrm{e}}{2 \mathrm{~m}} l$$

→ Velocity selector is a set up to select charged particles of a particular velocity from a beam passed through a space having crossed electric and magnetic fields.

Formulae

→ F = q $$(\vec{v} \times \vec{B})$$ (or) F = Bqυ sin θ

→ dB = $$\frac{\mu_0}{4 \pi} \cdot \frac{\mathrm{id} l \sin \theta}{\mathrm{r}^2}$$

→ B = $$\frac{\mu_0 n i r^2}{2\left(r^2+x^2\right)^{3 / 2}}$$

→ B = $$\frac{\mu_0 \mathrm{ni}}{2 \mathrm{r}}$$

→ B = $$\frac{\mu_0}{4 \pi} \frac{\mathrm{i}}{\mathrm{a}}\left(\sin \phi_2+\sin \phi_1\right)$$

→ B = $$\frac{\mu_0 \mathrm{i}}{2 \pi \mathrm{a}}$$

→ m = nia

→ B = μ0ni (At the centre of the solenoid)

→ B = $$\frac{\mu_0 n i}{2}$$ (At one of its ends of a solenoid)

→ $$\oint \overrightarrow{\mathrm{B}} \cdot \mathrm{d} \vec{l}=\mu_0 \mathbf{i}$$

→ F = $$\mathrm{q}[\overrightarrow{\mathrm{E}}+(\vec{v} \times \overrightarrow{\mathrm{B}})]$$

→ F = $$\mathrm{i}(\vec{l} \times \overrightarrow{\mathrm{B}})=\mathrm{Bi} l \sin \theta$$

→ τ = $$\overrightarrow{\mathrm{M}} \times \overrightarrow{\mathrm{B}}=\mathrm{MB} \sin \theta$$

→ i = $$\frac{\mathrm{C}}{\mathrm{BAN}} \theta$$

→ S = $$\frac{\mathrm{i}_{\mathrm{g}} \mathrm{G}}{\mathrm{i}-\mathrm{i}_{\mathrm{g}}}$$

→ R = $$\frac{\mathrm{V}}{\mathrm{i}_{\mathrm{g}}}-\mathrm{G}$$