Calculate the threshold frequency of photon for photoelectric emission from a metal of work function $0.1 \mathrm{eV}$.

What is the Brewster angle for air to glass transition? (Refractive index of glass $=1.5$ )

At a certain location in Africa, a compass points $12^{\circ}$ west of the geographic north. The north tip of the magnetic needle of a dip circle placed in the plane of magnetic meridian points above the horizontal. The horizontal component of the earth’s field is measured to be $0.16 \mathrm{G} .$ Specify the direction and magnitude of the earth’s field at the location.At a certain location in Africa, a compass points $12^{\circ}$ west of the geographic north. The north tip of the magnetic needle of a dip circle placed in the plane of magnetic meridian points above the horizontal. The horizontal component of the earth’s field is measured to be $0.16 \mathrm{G} .$ Specify the direction and magnitude of the earth’s field at the location.

Two long and parallel straight wires $A$ and $B$ carrying currents of $8.0 A$ and $5.0 \mathrm{~A}$ in the same direction are separated by a distance of $4.0 \mathrm{~cm}$. Estimate the force on a $10 \mathrm{~cm}$ section of wire A.

A $3.0 \mathrm{~cm}$ wire carrying a current of $10 \mathrm{~A}$ is placed inside a solenoid perpendicular to its axis. The magnetic field inside the solenoid is given to be $0.27 \mathrm{~T}$. What is the magnetic force on the wire?

What is the magnitude of magnetic force per unit length on a wire carrying a current of $8 \mathrm{~A}$ and making an angle of $30^{\circ}$ with the direction of a uniform magnetic field of $0.15 \mathrm{~T} ?$

A long straight wire carries a current of $35 \mathrm{~A}$. What is the magnitude of the field $\mathrm{B}$ at a point $20 \mathrm{~cm}$ from the wire?

State Biot-Savarts law. Derive an expression for magnetic field at the center of a circular coil of $n$-turns carrying current $-1$.

A straight wire carries a current of $10 \mathrm{~A}$. An electron moving at $10^{7} \mathrm{~m} / \mathrm{s}$ is at distance $2.0 \mathrm{~cm}$ from the wire. Find the force acting on the electron if its velocity is directed towards the wire.

Give one difference each between diamagnetic and ferromagnetic substances. Give one example of each.

A steady current flows in the network What will be the magnetic field at the center of the network?

A cyclotron is not suitable to accelerate electron. Why?