The galvanometer of resistance \(80~\Omega\) deflects a full scale for a potential of \(20\) mV. How much resistance is required for a voltmeter to deflect a full scale of \(5\) V to be made using this galvanometer?

1.	resistance of \(19.92~ \text{k} \Omega\) parallel to the galvanometer
2.	resistance of \(19.92~ \text{k} \Omega\) in series with the galvanometer
3.	resistance of \(20 ~\Omega\) parallel to the galvanometer
4.	resistance of \(20~ \Omega\) in series with the galvanometer

The resistances of three parts of a circular loop are as shown in the figure. What will be the magnetic field at the centre of \(O\) 
(current enters at \(A\) and leaves at \(B\) and \(C\) as shown)?

Consider six wires with the same current flowing through them as they enter or exit the page. Rank the magnetic field's line integral counterclockwise around each loop, going from most positive to most negative.

       
1. \(B>C>D>A\)
2. \(B>C=D>A\)
3. \(B>A>C=D\)
4. \(C>B=D>A\)

A magnetic dipole is under the influence of two magnetic fields. The angle between the field directions is \(60^{\circ}\), and one of the fields has a magnitude of \(1.2\times 10^{-2}~\text{T}\). If the dipole comes to stable equilibrium at an angle of \(15^{\circ}\) with this field, what is the magnitude of the other field?  \(\left[\text{Given} :   \sin   15^ \circ = 0 . 26\right]\)
1. \( 7.29 \times10^{-3} ~\text{T} \)
2. \( 4.39 \times10^{-3} ~\text{T} \)
3. \( 6.18 \times10^{-3} ~\text{T} \)
4. \(5.37 \times10^{-3} ~\text{T} \)

A square loop with a side \(l\) is held in a uniform magnetic field \(B\), such that its plane making an angle \(\alpha\) with \(B\). A current \(i\) flows through the loop. What will be the torque experienced by the loop in this position?
1. \(Bil^{2}\)

2. \(Bil^{2} \sinα\)

3. \(Bil^{2} \cosα\)

4. zero

Suppose a cyclotron is operated at an oscillator frequency of 12 MHz and a discharge radius of 53 cm. What is the resulting kinetic energy of the deuterons?
(Mass of deuteron, \(m=3.34\times10^{-27}\) kg)

1. 16.6 MeV
2. 12 MeV
3. 15 MeV
4. 14 MeV

A neutron, a proton, an electron and an \(\alpha\text-\)particle enter a region of the uniform magnetic field with the same velocity. The magnetic field is perpendicular and directed into the plane of the paper. The tracks of the particles are labelled in the figure. Which track will the \(\alpha\text-\)particle follow?
              

Which of the following statements about cyclotron is correct?

A charged particle is projected through a region in a gravity-free space. If it passes through the region with constant speed, then the region may have:
1. \(\vec{E}=0, \vec{B} \neq 0\)
2. \(\vec{E} \neq 0, \vec{B} \neq 0\)
3. \(\vec{E} \neq 0, \vec{B}=0\)
4. Both (1) & (2)

What is the primary function of the electric field in a cyclotron?

1. energize the charged particle.

2. bring the charged particle again and again into the field.

3. cancel the force due to the magnetic field.

4. guide charged particles to the exit part.