Physics Test 18...

A positive charge +Q is fixed at a point A. Another positively charged particle of mass m and charge +q is projected from a point B with velocity u as shown in the figure. The point B is at the large distance from A and at distance d from the line AC. The initial velocity is parallel to the line AC. The point C is at very large distance from A. The minimum distance (in meter) of +q from +Q during the motion is d 

A positively charged particle is released from rest in an uniform electric field. The electric potential energy of the charge

In a neon gas discharge tube Ne⁺ ions moving through a cross-section of the tube each second to the right is  electrons move towards left in the same time; the electronic charge being  the net electric current is

A cyclotron's oscillator frequency is 10 MHz. If the radius of its 'dees' is 60 cm, what is the kinetic energy of the proton beam produced by the accelerator? Given )

The earth’s magnetic field lines resemble that of a dipole at the centre of the earth. If the magnetic moment of this dipole is close to , the value of earth’s magnetic field near the equator is close to (radius of the earth = )

In the figure shown a square loop PQRS of side ‘a’ and resistance ‘1 unit’ is placed near an infinitely long wire carrying a constant current I. The sides PQ and RS are parallel to the wire. The wire and the loop are in the same plane. The loop is rotated by 180^o about an axis parallel to the long wire and passing through the mid points of the side QR and PS. The total amount of charge which passes through any point of the loop during rotation is

In an electrical circuit R, L, C and an a.c. voltage source are all connected in series. When L is removed from the circuit, the phase difference between the voltage the current in the circuit is π/3. If instead, C is removed from the circuit, the phase difference is again π/3. The power factor of the circuit is :

A thin prism of angle 15^o made of glass of refractive index  is combined with another prism of glass of refractive index . The combination of the prism produces dispersion without deviation. The angle of the second prism should be

The Young’s double slit experiment is performed with blue and with green light of wavelengths  respectively. If x is the distance of 4th maxima from the central one, then