The point form of Ampere law is given by
1. Curl(B) = I
2. Curl(D) = J
3. Curl(V) = I
4. Curl(H) = J

1. If both the assertion and the reason are true and the reason is a correct explanation of the assertion
2. If both the assertion and reason are true but the reason is not a correct explanation of the assertion
3. If the assertion is true but the reason is false
4. If both the assertion and reason are false

Three long wires, each carrying current i are placed parallel to each other. The distance between I and II is 3d, between II and III is 4 d and between III and I is 5d. Magnetic field at side of wire II is 

1. $\frac{5{\mathrm{\mu }}_0\mathrm{i}}{24\mathrm{\pi d}}$

2. $\frac{10{\mathrm{\mu }}_0\mathrm{i}}{24\mathrm{\pi d}}$

3. $\frac{15{\mathrm{\mu }}_0\mathrm{i}}{24\mathrm{\pi d}}$

4. $\frac{20{\mathrm{\mu }}_0\mathrm{i}}{24\mathrm{\pi d}}$

A closely wound solenoid of 2000 turns and area of cross-section 1.5 × 10^–4 m² carries a current of 2.0 A. It is suspended through its centre and perpendicular to its length, allowing it to turn in a horizontal plane in a uniform magnetic field 1.5 × 10^–2 T , making an angle of 30° with the axis of the solenoid. The torque on the solenoid will be?

1.  3 × 10^–3 N-m

2.  4.5 × 10^–3 N-m

3.  1.5 × 10^–2 N-m

4.  3 × 10^–2 N-m

Moving perpendicular to field \(B\), a proton and an alpha particle both enter an area of uniform magnetic field \(B\). If the kinetic energy of the proton is \(1~\text{MeV}\) and the radius of the circular orbits for both particles is equal, the energy of the alpha particle will be:
1. \(4~\text{MeV}\)
2. \(0.5~\text{MeV}\)
3. \(1.5~\text{MeV}\)
4. \(1~\text{MeV}\)

A very long straight wire carries a current I. At the instant when a charge +Q at point P has velocity $\overrightarrow{\mathrm{V}}$, as shown, the force on the charge is-

1.  Along OX

2.  Opposite to OY

3.  Along OY

4.  Opposite to OX

A uniform electric field and a uniform magnetic field are acting in the same direction in a certain region. If an electron is projected in the region such that its velocity is pointed along the direction of fields, then the electron: