A student performs an experiment to study the magnetic effect of current around a current carrying straight conductor with the help of a magnetic compass. He reports that
For a given battery, the degree of deflection on N-pole decreases when the compass is kept at a point farther away firm the conductor.
Is the given statement incorrect.

A student performs an experiment to study the magnetic effect of current around a current carrying straight conductor with the help of a magnetic compass. He reports that The direction of deflection of the magnetic compass increases when the current through the conductor is increased. Which of the above observations of the student appears to be wrong and why?

The magnetic field around a current carrying straight conductor is in concentric circles with the center of circle at a point where the conductor is not located. Is this statement true.

With the help of a necessary diagram, derive an expression for magnetic field due to straight current carrying conductor at any point.

The existence of negatively charged particle in an atom was shown by J.J. Thomson as a result of the studies of the passage of electricity through gases at extremely low pressure known as discharge tube experiments. When a high voltage of the order of 10,000 volts or more was impressed across the electrodes, some sort of invisible rays moved from the negative electrode to the positive electrode these rays are called as cathode rays. Cathode rays travel in straight path in absence of electrical and magnetic field . Cathode rays consist of material part and charged particles? Cathode rays produce X-rays and light is emitted when they strike on ZnS screen. Cathode rays penetrate through thin sheets of aluminium and other metals . They affect the photogenic plate and passes heating effect when they strike on metal foil. The raito of charge to mass i.e charge/mass is same for all the cathode rays irrespective of the gas used in the tube. The existence of positively charged particle in an atom was shown be E. Goldstein. He repeated the same discharge tube experiments by using a perforated cathode. It was observed that when a high potential difference was applied between the electrodes, not only cathode rays were produced but also a new type of rays were produced simultaneoulsy from anode moving towards cathode and passes through the holes or canal of the cathode. These termed as canal rays or anode rays. These rays travel in straight lines and consists of positively charged particles. These rays have kinetic energy and produces heating effect also. The e/m ratio of these rays is smaller than that of electrons. Unlike cathode rays, their e/m value is dependent upon the nature of the gas taken in the tube. These rays produced flashes of light on ZnS screen and can pass throughs thin metal foils. They can produce physical and chemical changes and are capable to produce ionisation in gases. Select the incorrect statement.

Two long straight, current-carrying condcutors , PQ and XY, are held a constant distance apart as shown in the figure. The conductors carry the magnitude of current in the same direction . A plan view form above the conductors is shown in the figure. The magnetic flux density B at a distance d from a long straight wire carrying a current I is given by B = 2.0 xx 10^-7 I/d Use this expression to explain why, under normal circumstances, wires carrying alternating current are not seen to vibrate.