In an ammeter, \(0.2 \%\) of the main current passes through the galvanometer. If the resistance of the galvanometer is \(G,\) the resistance of the ammeter will be:

1.	\({1 \over 499}G\)	2.	\({499 \over 500}G\)
3.	\({1 \over 500}G\)	4.	\({500 \over 499}G\)

Two identical long conducting wires \(({AOB})\) and \(({COD})\) are placed at a right angle to each other, with one above the other such that '\(O\)' is the common point for the two. The wires carry \(I_1\) and \(I_2\) currents, respectively. The point '\(P\)' is lying at a distance '\(d\)' from '\(O\)' along a direction perpendicular to the plane containing the wires. What will be the magnetic field at the point \(P?\)

Two similar coils of radius \(R\) are lying concentrically with their planes at right angles to each other. The currents flowing in them are \(I\) and \(2I,\) respectively. What will be the resultant magnetic field induction at the centre?

A millivoltmeter of \(25~\text{mV}\) range is to be converted into an ammeter of \(25~\text{A}\) range. The value (in ohm) of the necessary shunt will be:
1. \(0.001\)
2. \(0.01\)
3. \(1\)
4. \(0.05\)

An alternating electric field of frequency $\mathrm{\nu }$, is applied across the dees (radius=R) of a cyclotron that is being used to accelerate protons (mass=m). The operating magnetic field B, used in the cyclotron and the kinetic energy (K) of the proton beam, produced by it, are given by:

1. $\mathrm{B}=\frac{\mathrm{m\nu }}{\mathrm{e}}$ $\mathrm{and}$ $\mathrm{K}=2{\mathrm{m\pi }}^2{\mathrm{\nu }}^2{\mathrm{R}}^2$

2. $\mathrm{B}=\frac{2\mathrm{\pi m\nu }}{\mathrm{e}}$ $\mathrm{and}$ $\mathrm{K}={\mathrm{m}}^2{\mathrm{\pi \nu R}}^2$

3. $\mathrm{B}=\frac{2\mathrm{\pi m\nu }}{\mathrm{e}}$ $\mathrm{and}$ $\mathrm{K}=2{\mathrm{m\pi }}^2{\mathrm{\nu }}^2{\mathrm{R}}^2$

4. $\mathrm{B}=\frac{\mathrm{m\nu }}{\mathrm{e}}$ $\mathrm{and}$ $\mathrm{K}={\mathrm{m}}^2{\mathrm{\pi \nu R}}^2$

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:

1.  speed will decrease

2.  speed will increase

3.  will turn towards the left of the direction of motion

4.  will turn towards the right of the direction of motion

A beam of cathode rays is subjected to cross Electric (E) and magnetic fields(B). The fields are adjusted such that the beam is not deflected. The specific charge of the cathode rays is given by:

1. $\frac{B^2}{2V{E}^2}$

2. $\frac{2V{B}^2}{E^2}$

3. $\frac{\mathrm{2V}{E}^2}{B^2}$

4. $\frac{E^2}{2V{B}^2}$

(where V is the potential difference between cathode and anode)